Question

Solve -3-(a-2)=7a+15

Answer 1

Our answer is: a = -9/4

`\Large\textsl{Explanation}`

We are asked to solve the following equation -

`\mapsto\quad\sf{-3(-a-2)=7a+15}`

⇒ Distribute -3:

`\mapsto\quad\sf{3a+6=7a+15}`

`\mapsto\quad\sf{7a+15=3a+6}`

`\mapsto\quad\sf{7a-3a=6-15}`

`\mapsto\quad\sf{4a=-9}`

`\mapsto\quad\boxed{\sf{a=-\cfrac{9}{4}}}`

`\therefore` a = -9/4

Answer 2

I am assuming the questions wants us to solve for a.

`a = - 2`

Explanation:

'a' is common on both sides of the equation. Hence, gather them on the same side to make it easier.

`- 3 - (a - 2) - 7a = 15`

*Remember the signs change and are now opposite of what it used to be (such as positive to negative).

Solve using algebra (collect like terms).

`- (a - 2) - 7a = 15 + 3`

`- a + 2 - 7a = 18`

`- 8a = 18 - 2`

`a = 16 / - 8`

`a = - 2`