Question

Suppose x = 7 is a solution to the equation 4x - 2(x + a) = 8. Find the value of a that makes the equation true

Answer 1

a = 7

Explanation:

Answer 2

`a=3`

Explanation:

So we have the equation:

`4x-2(x+a)=8`

And we want to find a such that x = 7 is a possible solution.

To do so, substitute 7 for x. Thus:

`4(7)-2(7+a)=8`

Multiply the left and distribute the right:

`28-14-2a=8`

Subtract:

`14-2a=8`

Subtract 14 from both sides:

`-2a=-6`

Divide by -2: "

`a=3`

So, the value of a is 3.

And our equation would be:

`4x-2(x+3)=8`

And we're done!

Edit: Incorrect Answer