# Questions on Algebra: Operations with Signed Numbers answered by real tutors!

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Question 994684: Use the rule for order of operations to simplify the expression as much as possible
-2+3/(-1)+4(-5)=

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Use the rule for order of operations to simplify the expression as much as possible
-2+3/(-1)+4(-5)=
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Rule of Order:: PEMDAS
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no P
no E
M gives
-2+3/-1-20
D gives
-2-3-20
A gives
-25
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Cheers,
Stan H.
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Question 992897: ( ) + ( ) + ( ) =30, using these numbers find the numbers needed to give the sum
1,3,5,7,9,11,13,15 repetitions are allowed

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.
You cannot add three odd numbers and get an even solution.

Question 992470: One tractor can plow a field in 8 hours, and another in 10 hours. In how many hours can both tractors plow the field together ?
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1/x + 1/y = 1/z
1/8 + 1/10 = 1/z
5/40 + 4/40 = 1/z
9/40 = 1/z
9*z = 40*1
9z = 40
9z/9 = 40/9
z = 40/9 = 4.444 (approximate)

It will take approximately 4.444 hours to plow the field together.

Question 991308: how to write √52 to 2√17

Question 988527: Perform the operation. Give the answer in a + bi form.
-3/4-i

Question 988194: I'm asked to write an algebraic equation for this sentence: 14 less than 3 times a number is 5 more than half of the number. I was thinking maybe 3n-14+5, but it doesn't look correct. Thanks for your help~
Found 2 solutions by ikleyn, solver91311:
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.
3x - 14 = + 5.

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You left out a representation of the word "is" in your sentence. "is" means equals, as in "=".

Everything on the left side of the word "is" in your sentence needs to be represented in the left-hand side of your equation. Everything on the right side of the word "is" needs to be represented in the right-hand side of your equation. Notice that the word "number" representing something unknown is repeated on both sides of the word "is" in your sentence. What do you think that means?

Give this another try and write back with your results. I'll help you some more if you need it then.

John

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

Question 986817: when x=2 what is 2x²+3x-1
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Hi there,
If x = 2
= 2x^2 + 3x - 1
= 2(2)^2 + 3(2) - 1
= 8 + 6 - 1
= 13
Hope this helps :-)

Question 986885: -8(5-x)=
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.
-8(5-x) = -40 + 8x.

Question 986818: when x=2 what is 2x²+3x-1
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Replace every x with 2. Then evaluate with a calculator or use pencil/paper

Replace every x with 2

-------------------------------------------------------
So when , the value of is 13

They are operations on fractons.
I have tried this a few timess but keep getting it wrong. My answer was
5/9 divided by (-9/10)= ?
Next question is-
-10/9 divided by (-9/10)=?
my answer was 1, but I got it wrong, help?

Found 2 solutions by macston, stanbon:
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.
The simplest way to divide by a fraction is to multiply by its reciprocal:
.
==
.
==

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5/9 divided by (-9/10)= ?
(5/9) / (-9/10)
---
= (5/9) * (-10/9)
---
= -50/81
-------------------------
Next question is-
-10/9 divided by (-9/10)=?
---
(-10/9) / (-9/10)
---
= (-10/9)*(-10/9)
---
= 100/81
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Cheers,
Stan H.
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Question 985557: Set notation for y=3x-11
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Set notation for y=3x-11
--------
Ans: {(x,y) | y = 3x-11}
--------------------
Cheers,
Stan H.
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Question 980170: Insert operations and grouping symbols to make the following equations true:
3 3 3 3 3=1
3 3 3 3 3=9
I always get 3 when I try to answer this problem.
3×3÷3+3-3=3; ((3×3)+(3-3))÷3=3; and many more that I've tried.

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(3 + 3 x 3) ÷ 3 - 3 =1
(3 - 3 ÷ 3) x 3 + 3 =9

Thanks,
PRD
https://onlinepsa.wordpress.com

Question 874701: (X^2-2X-3)(x-3)
Answer by kekegeter (94)   (Show Source):
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(x^2-2x-3)(x-3)
x^2 x-x^2 *3-2xx+2x*3-3x+3*3
x^3-5x^2+3x+9

Question 892495: (-15)+8
Answer by kekegeter (94)   (Show Source):

Question 956315: (8x + 4y)(2x - 11y)
Answer by kekegeter (94)   (Show Source):
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8x*2x-8x11y+4y*2x-4y*11y
16x^1+1-88xy+8xy-44y^1+1
16x^2-80xy-44y^2

Question 976406: Please do help me as soon as possible. Because I really need it. Sorry for rushing you.
Simplify the following by removing the grouping symbols:
a. -[4-(-5)]-16
b. -18-[-4-(-8)]
c. -{4x-(3y-16x)}
d. -{16x-(12-3x)}
e. -{-4-[10-(-6)]}-[8-(-18)]
f. -{-9-[-12-(-7)]}-[-15-(-2)]

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Simplify the following by removing the grouping symbols:
a. -[4-(-5)]-16
b. -18-[-4-(-8)]
c. -{4x-(3y-16x)}
d. -{16x-(12-3x)}
e. -{-4-[10-(-6)]}-[8-(-18)]
f. -{-9-[-12-(-7)]}-[-15-(-2)]
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f. -{-9-[-12-(-7)]}-[-15-(-2)]
= -{-9-[-12+7]}-[-15+2]
= -{-9-[-5]}-[-13]
= -{-9-[-5]} + 13
= -{-9+5]} + 13
= -{-4} + 13
= 4 + 13
= 17
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You try the others, email via the TY note to check your work.

Question 975142:
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Question 974098: Order of operations is the math type of algebra I'm doing please could you help me understand why I can't get the right answer. I keep getting 6.5 and every were I've looks tell me it's 44 but doesn't explain please help me the math equation is 8×5÷10+5035×(3-1)^(2)
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8×5÷10+5035×(3-1)^(2)
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= 8×5÷10+5035×4
= 40/10 + 20140
= 20144
==================
You need to add some parentheses to eliminate ambiguities.
They're free.
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Also, use * (Shift 8) for multiply, not x.

Question 968336: Perform the indicated operations and if possible, simply
60/75 – 4/5 =

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...first simplify , divide both numerator and denominator by

Question 961476: what is the answer? plz |9-2x| < |4x|
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9 - 2x < 4x
Collect like terms
-2x - 4x < -9
-6x < -9
Divide both sides by the coefficient of x
-6x/-6 > -9/-6
x > 3/2
Note: when dividing with a negative co-efficient I.e (-6) the inequality sign change

Question 965426: Hi, how can u turn 7 more than x into algebraic expression? 7+x,or 7-x

Question 957878: What is 0.5% off of 315?
How do I do this on excel?

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=315*(1-0.5/100)

Question 950400: (12)(7)-(6)(19)
Found 2 solutions by macston, MathLover1:
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(12)(7)-(6)(19)=(84)-(114)=-30

Question 947549: hey I was wondering why -6*2 equals negative 12 not twelve isn't -6 times -2=12?
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-6*2 is the opposite of 6*2.

--FURTHER INSTRUCTIVE COMMENTARY---
The proof or at least logical demonstration should be found in your book. You can start this way:
You already understand that , basic fact, easily demonstrated with repeated additions.

You may already understand, -6*2 means the same as 2*(-6), which is

and since you can refer to a numberline using signed numbers, you will find
.

Now you want to take the next step and understand how , the positive number. Try THIS:

but theoretically this still is not a proof for you. What it shows is THE OPPOSITE OF NEGATIVE 12.
, the positive quantity.

This can not be made much easier.

Do not be thrown off by the need to read the notation.
-6*2 means exactly the same as (-1)*6*2, which is or should obviously be .

Question 946105: find the value of n.then check by adding - (5/8+1/8)+3/8=5/8+(1/8+n) n=
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solutions:
->
or
->

check:

round it to whole number

Question 945583: A book has 500 pages numbered 1, 2, 3… and so on. How many times does the digit 1 appear in the page numbers?
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The digit 1 sometimes appears more than once on the same page number,
so it appears a lot.
It appears at times as the first digit in pages 100 to 199.
It appears as the last digit times
(on page 1, and in other page numbers preceded by 1, 2, 3, ... 49).
It appears as the tens digit in 2-digit numbers (10, 11, ...19),
and also appears as the tens digit in many 3-digit page numbers,
times preceded by each of the digits 1, 2, 3,and 4.
So, the total count is
appearances of the digit 1.

NOTE:
That does not mean that there are 200 page numbers where the number 1 appears.
That would be a different question.
In that case, I would rename the page numbers as the 3-digit numbers
001, 002, 003, .... 498, 499, 000.
(I am using 001 for 1, 002 for 2, and so on up to 099 for 99, and I use 000 for 500).
Those are 500 3-digit ordered arrangements,
with 5 choices for the first digit,
and 10 choices for each of the other two digits.
There is a total of such arrangements.
How many contain the digit 1 at least once?
How many do not contain y=the digit 1 at all?
If we wanted to exclude the digit 1,
we could only use of the arrangements.
so pages contain the digit 1 at least once.

Question 943757: Adding rational expressions with different denominators: ax, bx
How do I get this into a single fraction in simplest form?
3+(8x+8y)/3x-(6x+8y)/9x
I can get it to this;
18x2 + 16xy + 27
————————————————
9
But then I am lost on how t get it further simplified.

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=

=

=

=

=

=

=

Question 943643: 4-x>2x+16

Question 943644: 3(3f-4)>5f-9

Question 943640: What is the domain for this rational expression? (m^2+2m-24)/(m^2-3m)
Found 2 solutions by MathLover1, josgarithmetic:
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the domain for this rational expression:

....denominator cannot be equal to zero
so, the domain will be all real numbers excluding values of that make and they are: and
the domain is:
{ element : and }
(assuming a function from reals to reals)

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The restriction is .

and .

Domain: AND AND .

Question 939531: How do you evaluate teh expression 4 -3/2
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How do you evaluate teh expression 4 -3/2
----
Convert 4 to halfs to get:
(8/2)-(3/2)
----
Ans: 5/2
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Cheers,
Stan H.
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Question 937190: Pls help me out in solving with an explanation:
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Can you clarify the queston ?
If you need more help or details you can contact me at:
mthman@gmail.com
Thanks

Question 934020: Algebra Find the unknown digit to make each statement ture
2.48 > 2.4n1 > 2.463 What goes in digit n and how do we determine this?
5.723 < 5.72n < 5.725
7.64 < 7.n5 < 7.68

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By using trial and error. By looking at the hundredth digit, we know that the first number of the hundred digit is 8 and the hundredth digit of the third number is 6. We have to find a value less than 8, but greater than 6. Therefore, we can assume that n is 7. Now, we plug in our values.

Plugging in our values, this statement is true and n can be 7.

By also using trial and error, we look this time the thousandth digit, we know that the first number of the digit is 3 and the third number of the digit is 5. We need to find a value greater than 3, but less than 5. A value that is greater than 3, but less than 5 would be 4. Plugging in 4 would be...

Correct.

Using the same method, we look at the tenth digit now, we know that the first number of the tenth digit is 6 and the third number of the digit is also 6. Since the first and third number of the tenth digit are the same, we look to the hundredth digit that the first number is 4 and the third number is 8. Relevant to the solution, the second number of the hundredth digit is 5. We want to find a value for n that makes the second number greater than 7.64, but less than 7.68. Through trial and error as usual, we discover that n must equal 6.

Plugging in the value of n. This statement now appears to be true.

Question 933782: -15 + 3 x -4 - 12 /-6
Do I go left to right, or do I do the multiplication first?

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BOTH of those. Understand that multiplication has "precedence" over additions and subtractions.

-15 + 3 x -4 - 12 /-6

The 3x stays as it is.

You CANNOT subtract the 12 from the -4 because DIVISION has precedence over addition or subtraction.

In your given expression, change ALL numbers to their signed forms, and use Commutative Property of Addition to combine like-terms.

simplified to

---
Maybe you meant the "x" to be multiplication operation symbol. If this be so, then as you go from left to right in the entire expression, to operations you do first must be the and the ; this makes your expression now like this:

and you now again start from left to right and do the additions or subtractions.

.

Question 931823: solve algebraically
4x^2+y^2=64
x^2+y^2=52

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solve algebraically
4x^2+y^2=64
x^2+y^2=52
------------------- Subtract

Question 927062: My equation is -20/5-(-3)^2 The answer I got using the order of operation is 5 but the algebra calculator says -13. This answer requires me to divide before doing exponent. Why would I not use order of operation?
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-20/5-(-3)^2 has the calculator thinking you mean

but what you really want is

so you need to enclose the denominator 5-(-3)^2 in parenthesis like this:

-20/(5-(-3)^2)

Question 926054: what is the greatest natural number of two dight and three dight
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Natural number definition: a positive integer or zero
so,
the largest digit natural number is
and
the largest digit natural number is

Question 925959: Graph f(x) = -3 + 1. Then reflect the graph of f(x) across the y-axis. Write a function. g(x) to describe the new graph. (you don't have to graph it, I don't understand what to graph)
Found 2 solutions by MathTherapy, josgarithmetic:
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Graph f(x) = -3 + 1. Then reflect the graph of f(x) across the y-axis. Write a function. g(x) to describe the new graph. (you don't have to graph it, I don't understand what to graph)

Your equation appears to be wrong!! Do you check your work before submitting it?