# Questions on Algebra: Linear Equations, Graphs, Slope answered by real tutors!

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Question 994759: I am trying to help my grand daughter with 8th grade math. It's not the math that I learned. So can you simplify how to get the answers that she needs and understand how we got the correct answer? Example: y = x -4, on a graph and write out the answer.

Thank you!

Answer by Alan3354(47455)   (Show Source):
You can put this solution on YOUR website!
I am trying to help my grand daughter with 8th grade math. It's not the math that I learned. So can you simplify how to get the answers that she needs and understand how we got the correct answer? Example: y = x -4, on a graph and write out the answer.
============
y = x-4 has no unique answer.
There are an infinite # of "answers."
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If you graph it, it's a straight, and every point on the line is a solution.
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dl the FREE graph software at
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Use Ins, then enter x-4
You can get a graph of the equation in your choice of color.

Question 994550: What happens yo the equation when y=x becomes y=x+3 ?
Answer by solver91311(20879)   (Show Source):
You can put this solution on YOUR website!

Up 3.

John

My calculator said it, I believe it, that settles it

Question 994463: How do I solve: y=x-3
Y=-3/4x + 4
I know how to do rise over run with whole numbers, just not fractions

Answer by Alan3354(47455)   (Show Source):
You can put this solution on YOUR website!
How do I solve: y=x-3
Y=-3/4x + 4
-------------
Sub for y
x-3 = -3/4x + 4
Assuming you mean (-3/4)x:
Multiply thru by 4 to eliminate fractions.
4x-12 = -3x + 16
7x = 28
x = 4
-------------
y = x-3
y = 1

Question 994439: A phone company has a monthly cellular data plan where a customer pays a flat monthly fee of $10 and then a certain amount of money per megabyte (MB) of data used on the phone. If a customer uses 20 MB, the monthly cost will be$11.20. If the customer uses 130 MB, the monthly cost will be $17.80. A. Find a linear equation for the monthly cost of the data plan as a function of x, the number of MB used. B. Interpret the slope and vertical intercept of the equation. C. Use your equation to find the total monthly cost if 250 MB are used. Answer by stanbon(69061) (Show Source): You can put this solution on YOUR website! A phone company has a monthly cellular data plan where a customer pays a flat monthly fee of$10 and then a certain amount of money per megabyte (MB) of data used on the phone. If a customer uses 20 MB, the monthly cost will be $11.20. If the customer uses 130 MB, the monthly cost will be$17.80.
A. Find a linear equation for the monthly cost of the data plan as a function of x, the number of MB used.
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You are given 2 points:: (20,10,21.20) ; (130,27.80)
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slope = (27.8-21.2)/(110) = 0.06
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Cost = 0.06x + b
Solve for "b"
21.20 = 0.06*20 + b
21.2 = 1.2 + b
b = 20
Cost = 0.06x + 20
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B. Interpret the slope and vertical intercept of the equation.
slope = 0.60 means $0.06 or 6 cents extra for each MB over 20 intercept =$20 for joining the plan and using less than 20 MB
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C. Use your equation to find the total monthly cost if 250 MB are used.
250-20 = 230 MB
C(230) = 0.06*230 + 20 = $33.80 ------- Cheers, Stan H. -------- Question 994440: 10 less than a number is -5 Answer by Timnewman(249) (Show Source): You can put this solution on YOUR website! Let the number be x, x-10=-5 x=-5+10 x=5 The number is 5 Question 994355: What is the equation of the line that has a slope of 2 and contains the point (-1,4) Answer by josgarithmetic(13975) (Show Source): You can put this solution on YOUR website! Use the point-slope form directly, as one method. Slope m, point (h,k), A line for them is . Question 994431: whats a number increased by nine is -6 Answer by stanbon(69061) (Show Source): You can put this solution on YOUR website! a number increased by nine is -6 ---- Equation: x + 9 = -6 x = -6-9 x = -15 -------------- Cheers, Stan H. ------------- Question 994385: You have$100 in your savings account and plan to deposit $20 each month. Write and graph a linear equation that represents the balance in your account. Answer by Boreal(1464) (Show Source): You can put this solution on YOUR website! At months =0 you have$100. that is the intercept.
The money increases by $20 a month, and that is the slope. y=20x+100, where x=the number of months you have been depositing. Question 994387: Four less than half a number is equal to 37 less than twice the number. How do you Translate the sentence into an equation and Solve the equation. Answer by stanbon(69061) (Show Source): You can put this solution on YOUR website! Four less than half a number is equal to 37 less than twice the number. How do you Translate the sentence into an equation and Solve the equation. ------- (1/2)x - 4 = 2x-37 ------ (3/2)x = 33 ---- (1/2)x = 11 x = 22 ------------- Cheers, Stan H. --------------- Question 994394: Write the slope-intercept form of an equation of the line with slope -9 and passes through the point (-2, -7). Found 2 solutions by Boreal, stanbon: Answer by Boreal(1464) (Show Source): You can put this solution on YOUR website! point slope formula y-y1=m(x-x1) y+7= -9(x+2). Notice that we are subtracting a negative, so we have to add. y+7=-9x-18 y= -9x-25 Answer by stanbon(69061) (Show Source): You can put this solution on YOUR website! Write the slope-intercept form of an equation of the line with slope -9 and passes through the point (-2, -7). -------- Form:: y = mx + b Solve for "b":: -7 = -9*-2 + b -7 = 18 + b b = -25 ----- Equation: y = -9x - 25 --------------- Cheers, Stan H. ----------- Question 994391: Write a justification for Line 2, Line 3, and Line 4. Explain why you chose each justification. Line 1 5x – 2 = 3x + 7 Line 2 2x – 2 = 7 Line 3 2x = 9 Line 4 x = 4.5 Found 2 solutions by Boreal, stanbon: Answer by Boreal(1464) (Show Source): You can put this solution on YOUR website! You may subtract 3x from both sides of an equation without changing the equation. You may add 2 to both sides of the equation without changing the equation. You may divide both sides of an equation by 2 without changing the equation. Answer by stanbon(69061) (Show Source): You can put this solution on YOUR website! Write a justification for Line 2, Line 3, and Line 4. Explain why you chose each justification. Line 1 5x – 2 = 3x + 7 Subtract 3x from both sides to get: Line 2 2x – 2 = 7 Add 2 to both sides to get Line 3 2x = 9 Divide both side by 2 to get Line 4 x = 4.5 ----- Cheers, Stan H. -------------- Question 994337: Please check whether each ordered pair is a solution to the equation. Equation y= 2/3x+5, ordered pair (3,8). I don't understand Answer by Fombitz(25151) (Show Source): You can put this solution on YOUR website! Plug the value in the equation. If it satisfies the equation, then it's a solution. False, so no it's not a solution. Question 994356: What is the equation of a line that has a slope of 0 and contains the point (-5,7) Answer by Fombitz(25151) (Show Source): You can put this solution on YOUR website! Use the point slope form of a line, Question 994317: Water freezes at 0 degrees Celsius, which is the same as 32 degrees Fahrenheit. Also water boils at 100 degrees Celsius, which is the same as 212 degrees Fahrenheit. (Use fractions in your answers.) (a) Use the freezing and boiling points of water to find a formula expressing Celsius temperature C as a linear function of the Fahrenheit temperature F. C = (b) What is the slope of the function you found in part (a)? Answer by josgarithmetic(13975) (Show Source): You can put this solution on YOUR website! Use the two points (32,0) and (212,100) to find the equation of the line. The ordered pairs are in a form, (F, C). Question 994314: what is an equation that is in general form and is perpendicular to and passes through the point (3,2) Answer by macston(4006) (Show Source): You can put this solution on YOUR website! . . Re-write in slope intercept form From this we know the slope is 4. The slope of the perpendicular line is the negative reciprocal (-1/4): Substitute the values from (3,2) to find b: . The equation: . Convert to general form: . Question 994313: write an equation parallel to , and how would I know that it is parallel? Answer by macston(4006) (Show Source): You can put this solution on YOUR website! . A parallel line has the same slope. Write the equation in slope-intercept form. . (Red line on graph below) The slope is (-7/3), so a parallel line: You can pick a y-intercept for b (other than (-4/3)), say 1: And re-write in general form: (Green line on graph below) . ANSWER: Equation for parallel line: 7x+3y=3 . Question 994303: I need help writing an equation of the vertical line that passes through the point (-5,7)??? Thank you in advance! Answer by KMST(3791) (Show Source): You can put this solution on YOUR website! A vertical line has the same value for all its points. A vertical line that passes through the point (-5,7) has the equation . Question 994180: find the equations that passes through the point (2,-2)and that is perpendicular to the line with equation y=2/3x-3 Answer by solver91311(20879) (Show Source): You can put this solution on YOUR website! Perpendicular lines have negative reciprocal slopes. Determine the slope of the given line, then calculate the negative reciprocal of this slope. Use the calculated slope and the given point in the point-slope form of a line: where are the coordinates of the given point and is the calculated slope. John My calculator said it, I believe it, that settles it Question 994127: correct graph of -4x + 3y = 6. Answer by ikleyn(988) (Show Source): Question 994092: Please help me find the linear equation for this by graphing the two intercept points x + y = 1 3x - y = -25 Answer by stanbon(69061) (Show Source): You can put this solution on YOUR website! Please help me find the linear equation for this by graphing the two intercept points x + y = 1 3x - y = -25 ----- Add and solve for "x":: 4x = -24 x = -6 ----- Solve for "y":: -6 + y = 1 y = 7 ------- Intersect point::(-6,7) ----- -------- Cheers, Stan H. ----------- Question 994012: Find an equation of the line containing the given pair of points. (-2,-1)(-9,-4) The equation of the line in slope-intercept form is y= ? Please help me solve this problem. Answer by KMST(3791) (Show Source): You can put this solution on YOUR website! If you have two points, and , you can find the slope, , of the line connecting them as . If you have the slope, , of a line and a point, , on that line (point can be the same as or ), you can write the equation of that line in form as . If you have the equation of that line in form, you can use algebra to transform that equation into an equivalent equation for that line in form by solving for . IN THIS CASE: and , so , and . An equation for the line in form, using point , is <--> . Solving for , <--><--><--> , gives you the one and only equation in form for that line. Question 993989: Convert equation from point slope form to slope intercept form. y-(-7)=-(12/5)(x-3) Found 2 solutions by MathLover1, fractalier: Answer by MathLover1(11324) (Show Source): You can put this solution on YOUR website! it means you need to solve for Answer by fractalier(2141) (Show Source): You can put this solution on YOUR website! Slope-intercept form is y = mx + b. Thus we must solve for y in y-(-7)=-(12/5)(x-3). We have then, after distributing, y + 7 = (-12/5)x + 36/5 Now subtract 7 (which is 35/5) and get y = (-12/5)x + 1/5 Question 993976: slope -1/4 through (-10,5) write in slope intercept form Found 4 solutions by MathLover1, rfer, stanbon, josgarithmetic: Answer by MathLover1(11324) (Show Source): You can put this solution on YOUR website! given: slope point (,) slope intercept form: where is a slope and y-intercept since we already know the slope, we need to find y-intercept and we can do it using given data ...plug in given ,, and and find so, your equation is: Answer by rfer(15570) (Show Source): Answer by stanbon(69061) (Show Source): You can put this solution on YOUR website! slope -1/4 through (-10,5) write in slope intercept form ---- Form: y = mx + b Solve for "b":: 5 = (-1/4)(-10) + b ----- 5 = (5/2) + b b = (5/2) ------ Equation: y = (-1/4)x + (5/2) -------- Cheers, Stan H. -------- Answer by josgarithmetic(13975) (Show Source): You can put this solution on YOUR website! Point-slope form, -----now in slope-intercept form Question 993942: 1/2x+2y=6 Answer by Alan3354(47455) (Show Source): You can put this solution on YOUR website! Do you have a question? Question 993919: Graph the linear equation by finding and plotting the intercepts. Show all work and write each intercept as an ordered pair. You may draw your graph on the grid below or create your own graph. 3x-5y=15 x-intercept = y-intercept = Answer by rfer(15570) (Show Source): You can put this solution on YOUR website! x-intercept is when y=0 (5,0) y-intercept is when x=0 (0,-3) Question 993915: Given a line with equation 6x-y=5. Write an equation in point-slope form of the line perpendicular to the given line through the point (2, -3). Answer by josgarithmetic(13975) (Show Source): You can put this solution on YOUR website! Slope of a parallel line, . Slope of a perpendicular line, because this is the negative reciprocal of 6. Point-slope equation form for the line containing point (2,-3) and perpendicular, Question 993918: Convert the equation y-(-7)= -(12/5)(x-3) to slope-intercept form, y=mx+b Answer by josgarithmetic(13975) (Show Source): You can put this solution on YOUR website! This was explained already less than a day ago. An explanation can be understood and skills readily applied from the discussion here: http://www.algebra.com/algebra/homework/Coordinate-system/Coordinate-system.faq.question.993811.html Question 993916: Convert the equation y-(-7)=-(12/5)(x-3) to standard form,Ax+By=C , where A, B, and C are integers and A > 0. Answer by MathLover1(11324) (Show Source): You can put this solution on YOUR website! ....both sides multiply by to get a rid of fraction =>standard form, , where , , and are integers and Question 993686: Given a line with equation . Write an equation in point-slope form of the line perpendicular to the given line through the point (2, -3). Answer by solver91311(20879) (Show Source): You can put this solution on YOUR website! Find the slope of the given line. Then calculate the negative reciprocal of that slope. Use the calculated slope and the given point in the point-slope form: where are the coordinates of the given point and is the calculated slope. John My calculator said it, I believe it, that settles it Question 993687: The manager at a local Best Buy store kept track of daily sales of the iPhone 6 when it was first introduced. He noticed that sales were very high at first, but showed a steady decrease. For example, on day 5 after the phones first went on sale, the store sold 238 iPhone 6’s, but on day 10 after the phones first went on sale, the store sold only 153 iPhone 6’s. Assume that the relationship between number of days since the phone became available and number sold is linear and, let x = the number of days since the phone was released and y = number of phones sold at this Best Buy store. a) Write two ordered pairs to represent the sales on the days described. b) Find the slope of the line through those ordered pairs. c) Write an equation in point-slope form of the line. y d) Convert the equation to slope-intercept form. e) Explain what the slope and the y-intercept mean in the context of this problem. Answer by Boreal(1464) (Show Source): You can put this solution on YOUR website! (5,238) (10,153) ======= slope is (153-238)/(10-5)= -85/5 = -17 ======== y-y1= -17(x-x1). use either ordered pair. This is the point slope approach. y-238= -17(x-5));;point slope formula y-238= -17x+85 y= -17x+323 slope-intercept form. ===== Slope of -17 means that every day, 17 fewer iPhones are being sold. Intercept of 0 means that on the first day 323 were sold. Often, y-intercepts are not helpful but may be useful here. Question 993685: Write in point-slope form, , the equation of the line through the two points (3,-7) and (-2,5) Answer by josgarithmetic(13975) (Show Source): You can put this solution on YOUR website! Slope . Fitting into the form using either point, choosing here (3,-7), . Question 993692: Find an equation of the line that passes through (0,7) and is parallel to y=1/4(x)+6 Answer by Boreal(1464) (Show Source): You can put this solution on YOUR website! Edited the question above. parallel lines have the same slope The slope of the line given is (1/4) point slope formula with m=1/4 y-y1=(1/4)(x-x1) y-7=(1/4)(x-0) y=(1/4)x +7 Question 993684: Find the slope of the line through the points (3, -7) and (-2, 5). Answer by fractalier(2141) (Show Source): You can put this solution on YOUR website! Slope is found by m = (y2 - y1) / (x2 - x1) m = (5 - (-7)) / (-2 - 3) m = 12/(-5) = -12/5 Question 993671: Write the equation of the line that satisfies the given conditions. Express the final equation in standard form. x-intercept is -2 and the y-intercept is 5 Answer by Cromlix(3061) (Show Source): You can put this solution on YOUR website! Hi there, First gradient = 5/2 = 2.5 (y distance/x distance) Then you have the y intercept = 5 (c) y = mx + c y = 2/5x + 5 Hope this helps :-) Question 993663: Write the slope-intercept form of an equation of the line with slope -0.7 and y-intercept -4 Answer by Cromlix(3061) (Show Source): You can put this solution on YOUR website! Hi there, Slope = -0.7 y intercept -4 Using y = mx + c y = -0.7x -4 Hope this helps :-) Question 993664: Write the slope-intercept form of an equation of the line with slope -9 and passes through the point (4, 6). Answer by Cromlix(3061) (Show Source): You can put this solution on YOUR website! Hi there, Using equation y - b = m(x - a) m = -9 (a,b) = (4,6) y - 6 = -9(x - 4) y - 6 = -9x + 36 y = -9x + 36 + 6 y = -9x + 42 Hope this helps :-) Question 993556: Given an equation of a line, find equations for lines parallel or perpendicular to it going through specified points. Find the appropriate equations and points from the table below. Simplify your equations into slope-intercept form. Write the equation of a line parallel to the given line but passing through the given point. y=-2/3x + 2; (9,-3) Answer by solver91311(20879) (Show Source): You can put this solution on YOUR website! Parallel lines have identical slopes. Determine the slope of the given line by inspection since the given equation is in slope-intercept form. Then use this slope and the given point to provide the values for the point-slope form: where are the coordinates of the given point and is the given or calculated slope. John My calculator said it, I believe it, that settles it Question 993544: Word problem: The total cost for bowling includes the fee for shoe rental plus a fee per game. The cost of each game increases the price by$4. After 3 games, the total cost with shoe rental is \$14. Question: Write an equation to represent the total cost "y" to rent shoes and bowl "x" games? second Question: How much is shoe rental? How is this represented in the equation?
I think answer is: y=X

Answer by solver91311(20879)   (Show Source):
You can put this solution on YOUR website!

Since X and x are two entirely different things, then no one can say that your "I think" answer is actually wrong. However, your answer certainly isn't very useful or descriptive of the problem you are trying to model. Why don't you take some time to explain what you mean by y = X and why you think that is the answer?

John

My calculator said it, I believe it, that settles it

Question 993519: Given the line with the equation : y=3
a) Find at least three ordered pairs that satisfy the equation.

b) Find the slope of the line.

c) Graph the line. You may draw your graph on the grid below or create your own graph.

Answer by josgarithmetic(13975)   (Show Source):
You can put this solution on YOUR website!
(a)
y is 3 and no restriction is placed on x. The three or more points can be (anyRealNumberYouWant, 3).

(b)
Slope?
y is 3, everywhere. No change vertically; any change you want horizontally. Slope? 0.

(c)
Graphing is obvious. Explained.