L O.

# help solving solutions

1.  Simplify    x-y    +    x+y
x+y          x-y

I have zero since x-y crosses out x-y and x+y crosses out x+y

2.  solve 12x^2 + 7x = 10

I am trying to use (-3x + 4) (-4x + 3)

3.  simplify    x^2 -5x + 4
x -1

my answer is x - 4.  Is this correct?

4.  simplify  9x^2 - 3x
3x

my answer is 3x-1.  Is this correct?

## 4 Answers By Expert Tutors

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5 (3)

Tutoring in Precalculus, Trig, and Differential Calculus

Steve S.

This "(12x^2 - 8x) (+ 15x - 10)" implies multiplication of two numbers, which is wrong.
It should be "(12x^2 - 8x) + (15x - 10)", the addition of two numbers.
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03/29/14

Stephen W.

tutor
Maybe technically, but since the binomials are multiplied later to equal zero, I felt this would not be useful for the student to understand the problem. In fact, I felt it would distract from learning, in this case. Different techniques. Hopefully she gets it, one way or the other.
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03/29/14

L O.

Would my answer still be 2/3 and -5/4  ??
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03/29/14

Stephen W.

tutor
In this case, yes, if the whole "technically they are added" doesn't confuse you. Sometimes the first term in the second parenthesis is a negative, and it impacts the problem dramatically, which is why I skipped over that. After all, you needed help on this specific problem, not theoretical problems that may come your way.
Congrats for figuring out the other solution! It sounds like you are getting it.
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03/29/14

L O.

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03/29/14

L O.

For problem #1

x-y/x +y   +  x+y/x-y,  I got 2+2=4   (Is this correct?)
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04/04/14

Stephen W.

tutor
The final answer is 2(x2 + y2)/ (x2 - y2)
Sorry for any confusion!
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04/04/14

L O.

Thank you very much I think I now understand
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04/05/14

Tutor
5.0 (34)

Homeschool Mom Available For Tutoring

Tutor
4.8 (4)

Mathematics professor at Community Colleges

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