# Are These 2 Linear Equations Correct?

#### MathClown

The First One: 8(5-3x)-4(2+3x)=3

Expansion: -24x -12x 40-8 =3

Combine:-36x 32 =3

Shift: -36x = 3-32= -29

Solution: x= -29/-36

The Second One: 9(1+x)-8(x+2)= 2x

Expansion: 9x-8x 9-16 =2x

Combine: x -7 =2x

Shift: (x-2x) -7= 2x -2x

-x = -7

Solution: x= -7/-1

Is my formula for solving these equations correct (there are other ways but I thought my method is the easiest, or am I wrong?)? And are my solutions correct? If they're wrong, could you show me where I went wrong? Thanks guys!

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#### Prove It

MHF Helper
These are very hard to read as you keep forgetting plus and minus signs! But your logic is fine. The first is correct. The second is not.

You are correct up to \displaystyle \displaystyle \begin{align*} x - 7 = 2x \end{align*}, now subtract \displaystyle \displaystyle \begin{align*} x \end{align*} from both sides to find \displaystyle \displaystyle \begin{align*} -7 = x \end{align*}.

• MathClown

#### MathClown

These are very hard to read as you keep forgetting plus and minus signs! But your logic is fine. The first is correct. The second is not.

You are correct up to \displaystyle \displaystyle \begin{align*} x - 7 = 2x \end{align*}, now subtract \displaystyle \displaystyle \begin{align*} x \end{align*} from both sides to find \displaystyle \displaystyle \begin{align*} -7 = x \end{align*}.
For the second one, WolframAlpha says the answer is x=7/-1???

#### Prove It

MHF Helper
For the second one, WolframAlpha says the answer is x=7/-1???
Which is equal to -7...

#### MathClown

Which is equal to -7...
So WolframAlpha got it wrong? The final simplified answer is just x=-7? Is that what you're getting at? Or simply -7 since you're subtracting both x variables.

Remember that when positive number is divided or multiplied by negative number, answer is negative. Wolfram alpha gave you $$\displaystyle \frac{7}{-1}=-7$$. So both Wolfram Alpha and Prove It are correct.