Question

How do you solve and check your solution given `-3.4=0.4x`?

Answer 1

`x = -8.5`
... see below :)

Explanation:

When it says to solve, it means to find what the unknown variable equals to. So you want to isolate x to find what x is.

`-3.4=0.4x`

`-3.4/0.4=(0.4x)/0.4`

`-8.5=x`

To check if what we got is correct, we can input the answer back into the equation. So since we found that x=-8.5, we want to replace x with -8.5

`-3.4=0.4x`

`-3.4=0.4(-8.5)`

`-3.4=-3.4`

The left side is equal to the right side, so therefore we know that our answer is correct.

Answer 2

Find a value for `x` and then substitute it back into the original equation to see if it is true.

Explanation:

We are told `-3.4 = 0.4x`

Therefore, to begin, we need find a value for `x`. To do this we simply divide by the coefficient in front of `x` , in this case `0.4`

`therefore` `(-3.4/0.4) = x`

`therefore x =-17/2`

To check we substitute the values of `x` back into the original equation to see if it is true.

Subbing `-17/2` we get `-3.4 = 0.4(-17/2)`

which `-3.4 = -3.4`