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# Recent problems solved by 'oberobic'

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 Angles/526390: Two angles are supplements. The larger angle is 30 more than three times the smaller. Find the measures of these two angles.1 solutions Answer 348479 by oberobic(2304)   on 2011-11-04 20:41:43 (Show Source): You can put this solution on YOUR website!x + y = 180 x = 3y + 30 substitute 3y+30 +y = 180 4y = 150 y = 37.5 degrees x = 3*37.5+30 x = 142.5 degrees . Done.
 Distributive-associative-commutative-properties/526391: How do you solve for 6x^3=3x^2+3x 1 solutions Answer 348478 by oberobic(2304)   on 2011-11-04 20:37:31 (Show Source): You can put this solution on YOUR website!6x^3 = 3x^2 + 3x 6x^3 - 3x^2 -3x = 0 3x*(2x^2 -x -1) = 0 3x*(2x+1)(x-1) = 0 . x = 0, -1/2, 1 .
 Linear_Equations_And_Systems_Word_Problems/526293: The owner of a pizza parlor wants to make a profit of 80% of the cost for each pizza sold. If it costs \$8.50 to make a pizza, at what price should each pizza be sold? 1 solutions Answer 348476 by oberobic(2304)   on 2011-11-04 20:32:55 (Show Source): You can put this solution on YOUR website!80% of the cost is .8 * 8.50 = 6.80 . so the sales price should be the cost + required profit 8.50 + 6.80 = 15.30 . or you could say he need to sell for 100% of cost + 80% of cost = 180% of the cost 1.8*8.50 = 15.30 . Done.
 Travel_Word_Problems/526382: traveling 60 to 70 miles per hour for 3 to 4 hours estimate how many miles you would travel1 solutions Answer 348471 by oberobic(2304)   on 2011-11-04 20:14:45 (Show Source): You can put this solution on YOUR website!You are trying to determine the range of values from a minimum value to a maximum. The minimum will be the product 60 miles/hr * 3 hr = 180 miles. The maximum will be the product 70 miles/hr * 4 hr = 280 miles.
 Graphs/526373: Write the equation for the line: with y-intercept -1 and perpendicular to 3x-2y=6. a. 3x+2y=6 b. 2x+3y=6 c. 2x-3y=-3 d. 2x-3y=3 e. 2x+3y=-3 1 solutions Answer 348467 by oberobic(2304)   on 2011-11-04 20:10:45 (Show Source): You can put this solution on YOUR website!Write the equation for the line: with y-intercept -1 and perpendicular to 3x-2y=6. . y = mx + b y = mx -1 will have a y-intercept of (0,-1) . Get 3x -2y = 6 into slope-intercept form. . 3x -2y = 6 -2y = -3x +6 y = 3/2*x +3 . The line perpendicular to this line will have a slope that is the inverse reciprocal of m = 3/2 which is -2/3 and b = -1. . y = -2/3*x -1 . y-intercept = (0,-1) x-intercept = the point where y = 0. So set y=0 and solve for x. 0 = -2/3*x -1 2/3*x = -1 2x = -3 x = -3/2 (-3/2, 0) . In the following graph: the red line is y = 3/2*x +3 the green line is y = -2/3*x -1 . . Looking back at the question, it asks for the equation in standard form. . y = -2/3*x -1 multiply by 3 to eliminate fraction 3y = -2x -3 add 2x to both sides 2x +3y = -3 . Done.
 Probability-and-statistics/526378: 3x - 4= 21 solutions Answer 348464 by oberobic(2304)   on 2011-11-04 19:54:14 (Show Source): You can put this solution on YOUR website!3x -4 = 2 . Add 4 to both sides . 3x -4+4 = 2+4 3x = 6 . Divide both sides by 3 . 3x/3 = 6/3 . x = 2
 test/526362: (x-3)(x-5)=91 solutions Answer 348462 by oberobic(2304)   on 2011-11-04 19:50:36 (Show Source): You can put this solution on YOUR website!(x-3)(x-5)=9 . x^2 -5x -3x +15 = 9 . x^2 -8x +15-9 = 0 . x^2 -8x +6 = 0 does not factor . complete square . x^2 -8x = -6 . x^2 -8x + 16 = -6+16 . (x-4)^2 = 10 . x-4 = +sqrt(10) or x-4 = -sqrt(10) . x = -sqrt(10) +4 = .8377223398316205 . x = +sqrt(10)+4 = 7.16227766016838 .
 Rectangles/526370: The area of the rectangle is 80 square centimeters. If the perimeter is 36 centimeters, find the length and width of the rectangle.1 solutions Answer 348459 by oberobic(2304)   on 2011-11-04 19:36:29 (Show Source): You can put this solution on YOUR website!P = 2(L+W) P = 36 2L + 2W = 36 . L * W = 80 so L = 80/W . substitute . 2(80/W) +2W = 36 . multiply both sides by W to eliminate the fraction . 2(80) + 2W*W = 36W . divide both sides by 2 . 80 + W^2 = 18W . W^2 -18W +80 = 0 . factor . (W -8)(W-10) = 0 . W = 8 or 10 which means L = 10 or 8 respectively . Answer: Length = 10 and Width = 8 OR Length = 8 and Width = 10. . Done.
 Equations/526368: I am learning how to solve equations in two steps with positives and negative's. I have a test on tuesday so I need help please. How do I solve this type of exercise?: 1) 10p + 9 - 11 - p = -2(2p + 4) -3(2p - 2) 2) -3(1 + 6r) = 14 - r 3) -4k + 2(5k - 6) = -3k - 39 1 solutions Answer 348458 by oberobic(2304)   on 2011-11-04 19:25:57 (Show Source): You can put this solution on YOUR website!(1) 10p +9-11 -p = -2(2p+4) -3(2p-2) 10p -p +9-11 = -4p -8 -6p +6 9p -2 = -4p -10p -8+6 9p -2 = -14p -2 23p = 0 p = 0 . (2) -3(1+6r) = 14-r -3 -18r = 14 -r -18r = 17 -r -17r = 17 r = -1 . (3) -4k +2(5k-6) = -3k -39 -4k +10k -12 = -3k -39 6k -12 = -3k -39 9k -12 = -39 9k = -27 k = -3
 Travel_Word_Problems/526286: A freight train leaves a station at 5 A.M and travels North at 55 mph. At 6 A.M, a passanger train leaves on a parallel track and travels North at 60 mph. How long will it take the passanger train to overtake the freigh train? 1 solutions Answer 348456 by oberobic(2304)   on 2011-11-04 19:09:39 (Show Source): You can put this solution on YOUR website!Start with the distance equation: d=r*t . Train 1. d = 55t . Train 2. d = 60(t-1) . When Train 2 overtakes Train 1, they will have traveled the same distance. . d=d so 55t = 60(t-1) 55t = 60t -60 -5t = -60 t = 12 . Train 1 will have been traveling for 12 hr when Train 2 overtakes it. Train 2 will have been traveling for 11 hr when it overtakes Train 1. . Check: Will they have traveled the same distance? 55*12 = 660 60*11 = 660 Correct. . Done.
 Square-cubic-other-roots/525986: 3sqrt36+4sqrt41 solutions Answer 348290 by oberobic(2304)   on 2011-11-03 21:24:07 (Show Source):
 Linear-equations/525975: graph of the line 3x + 4y = 9 y = 4x – 5. show graph and Use the graph to find the slope of the line1 solutions Answer 348288 by oberobic(2304)   on 2011-11-03 21:20:41 (Show Source): You can put this solution on YOUR website!3x + 4y = 9 4y = -3x +9 y = -3/4*x + 9/4 . slope = -3/4 . y = 4x -5 . slope = 4 .
 Graphs/525926: graph y = -x, y = -3x1 solutions Answer 348276 by oberobic(2304)   on 2011-11-03 20:51:41 (Show Source):
 Age_Word_Problems/525937: Rebecca's mother is 4 times as old as Rebecca is now. In 6 years, Rebecca's mother will be 3 times as old as Rebecca will be then. What is Rebecca's age now, in years?1 solutions Answer 348275 by oberobic(2304)   on 2011-11-03 20:49:01 (Show Source): You can put this solution on YOUR website!M = 4*R . In 6 years M+6 R+6 . (M+6) = 3*(R+6) . substitute . (4*R +6) = 3*(R+6) . 4R +6 = 3R + 18 . R = 12 M = 4*12 = 48 . check in 6 years M+6 = 54 12+6 = 18 3*18 = 54 Correct . Answer: Rebecca is 12 years old. . Done.
 Travel_Word_Problems/525972: My son got a red light camera ticket Question: He is driving at 40 mph, the light had been red for 30 seconds when they snapped his picture. How far away (in feet) was he when the light had first turned red?1 solutions Answer 348272 by oberobic(2304)   on 2011-11-03 20:37:27 (Show Source): You can put this solution on YOUR website!(40 miles/hr) / (60 min/hr) = 2/3 mile/min . The light had been red for 30 seconds = 1/2 minute . 1/2 min * 2/3 mile/min = 1/3 mile . 1/3 mile * 5280 ft/mile = 1760 ft
 Expressions-with-variables/525920: 2x-3y=-24 x+6y=18 1 solutions Answer 348271 by oberobic(2304)   on 2011-11-03 20:29:34 (Show Source): You can put this solution on YOUR website!2x -3y = -24 x + 6y = 18 . multiply the first equation by 2 and then add . 4x -6y = -48 x + 6y = 18 -------------- 5x = -30 . x = -6 . substitute to find 'y' . x + 6y = 18 -6 + 6y = 18 6y = 24 y = 4 . Use the other equation to check the answer. 2x -3y = 2(-6) -3(4) = -12-12 = -24 Correct. . Answer: x = -6 and y = 4 . Done.
 Equations/525957: A team played 5 more games this season, than last season. Last season, they won 60% of their games. This season, they won 55% of their games. The team won the same number of games, both seasons. Find the number of games played, in each season.1 solutions Answer 348267 by oberobic(2304)   on 2011-11-03 20:16:56 (Show Source): You can put this solution on YOUR website!x = games played last season .6*x = games won last season . y = games played this season .55*y = games won this season y = x+5 . .6x = .55y . .6x = .55(x+5) . multiply by 100 to eliminate decimals . 60x = 55(x+5) . 60x = 55x + 275 . 5x = 275 . x = 55 games played last season . x+5 = 60 games played this season . Always check your answer. . .6 * 55 = 33 games won .55 * 60 = 33 games won Correct.
 Graphs/525943: what is the y-intercept of the graph of 9+x/2= -5+5?1 solutions Answer 348265 by oberobic(2304)   on 2011-11-03 20:08:45 (Show Source): You can put this solution on YOUR website!9 + x/2 = -5+5 9 + x/2 = 0 x/2 = -9 x = -18 Regardless of the value of 'y', x = -18. The means the slope would have a value for y-y1 divided by 0, which is undefined. So, x = -18 is a vertical line crossing the x-axis as (-18,0). There is no y-intercept because x never = 0.
 Finance/525946: slope=4/3, y-intercept=01 solutions Answer 348264 by oberobic(2304)   on 2011-11-03 20:04:50 (Show Source): You can put this solution on YOUR website!y = mx +b y = 4/3x +0 (0,0) is y=intercept and x-intercept .
 Geometric_formulas/525881: find a value for k so that the line through (6,-3) and (k,-4) is parallel to the line with the equation y=5x-7.1 solutions Answer 348260 by oberobic(2304)   on 2011-11-03 19:08:44 (Show Source): You can put this solution on YOUR website!The line parallel to y = 5x -7 will have a slope of 5. . With the two points given, you can find 'k'. . m = 5 . m = (-3-(-4)) / (6-k) . 5 = 1/ (6-k) . 5*(6-k) = 1 . 6-k = 1/5 -k = 1/5 - 6 k = -1/5 + 30/5 = 29/5 = 5 4/5 = 5.8 so the second point is (29/5,-4) . y = 5x + b . use one of the points to find 'b' . -3 = 5*6 + b -33 = b . y = 5x - 33 . In the following graph: the red line is y = 5x -7 the green line is y = 5x -33 .
 Equations/525400: this test is worth 150 points. suppose your score is 126 points. what is your percent on the test?1 solutions Answer 348104 by oberobic(2304)   on 2011-11-02 22:05:16 (Show Source): You can put this solution on YOUR website!126/150 * 100 = 84%
 Polygons/525428: what is the number of sides of a polygon if the sum of all the interior angles equal 3780 degrees1 solutions Answer 348103 by oberobic(2304)   on 2011-11-02 21:59:28 (Show Source): You can put this solution on YOUR website!For a polygon the sum of the interior angles = (n-2)*180 . (n-2)*180 = 3780 180n -360 = 3780 180n = 3420 n = 19 . Done.
 Numbers_Word_Problems/525429: Six more than twice a number is the same as seven times the sum of the number and 3. Find the number. 2n+6=7(n+3) n=31 solutions Answer 348102 by oberobic(2304)   on 2011-11-02 21:56:17 (Show Source): You can put this solution on YOUR website!2x+6 = 7(x+3) 2x +6 = 7x + 21 -5x = 15 x = -3 . Always check your answer. 2x+6 = 2*(-3)+6 = -6 + 6 = 0 7(x+3) = 7(-3+3) = 7*0 = 0 . Answer: x = -3 . Done.
 test/525415: 1 solutions Answer 348100 by oberobic(2304)   on 2011-11-02 21:52:40 (Show Source): You can put this solution on YOUR website!Ask a question.
 Rectangles/525353: The length of a rec is 3 more than twice the width. What are the dimensions if the perimeter is 511 solutions Answer 348098 by oberobic(2304)   on 2011-11-02 21:46:01 (Show Source): You can put this solution on YOUR website!L = 2W+3 . 2(L+W) = 51 . substitute . 2(2W+3+W) = 51 4W +6 +2W = 51 6W = 45 W = 45/6 = 7 1/2 L = 2W+3 = 18 P = 25 1/2 *2 = 51 . Answer: L = 18, W = 7 1/2 . Done.
 Problems-with-consecutive-odd-even-integers/525416: Two integers have a sum of -9 and a dfference of 5. What are the integers?1 solutions Answer 348096 by oberobic(2304)   on 2011-11-02 21:41:34 (Show Source): You can put this solution on YOUR website!x - y = 5 x + y = -9 ----------- 2x = -4 x = -2 . -2 -y = 5 -y = 7 y = -7 . -2+(-7) = -9 -2-(-7) = 5 . Answer: The two integers are -2 and -7. . Done.
 Money_Word_Problems/525388: Monse bought a new skirt and a pair of high heels. The shoes cost 3 times as much as the skirt. She paid for the items with two \$100 bills, and received \$80 in change. How much did the shoes cost?1 solutions Answer 348095 by oberobic(2304)   on 2011-11-02 21:37:34 (Show Source): You can put this solution on YOUR website!x = cost of shoes y = cost of skirt . x = 3y . 3y + y = 200 - 80 . 4y = 120 . y = 30 . x = 3y x = 90 . x + y = 120 . Answer: The skirt cost \$30 and the shoes cost \$90.
 Linear-equations/525408: Can you please help me with the graghing linear equation for {x+3y=9}?1 solutions Answer 348094 by oberobic(2304)   on 2011-11-02 21:33:39 (Show Source): You can put this solution on YOUR website!x + 3y = 9 . Get the equation into slope-intercept form. . 3y = -x +9 y = -x/3 +3 . slope = -1/3 . y-intercept = (0,3) . x-intercept can be found by setting y=0 and solving for x. 0 = -1/3*x + 3 1/3*x = 3 x = 9 (9,0) . With two points you can draw a line. .
 test/525407: solve each equation by finding square roots. if the equation has no solution, write no solution k^2 = 49 1 solutions Answer 348093 by oberobic(2304)   on 2011-11-02 21:27:52 (Show Source): You can put this solution on YOUR website!k^2 = 49 k = sqrt(49) k = 7 or -7
 Rectangles/525405: Find the area of the rectangle. the rectangle has a side of 2x and a side of x1 solutions Answer 348092 by oberobic(2304)   on 2011-11-02 21:27:07 (Show Source): You can put this solution on YOUR website!Area = 2x * x = 2x^2
 test/525404: 1 solutions Answer 348091 by oberobic(2304)   on 2011-11-02 21:25:39 (Show Source): You can put this solution on YOUR website!Ask a question.