Question

Moniker used substitution to solve this system of equation. Which equation could be the result of her first step

Answer 1

i agree with zealous

Answer 2

`3a+a-15=225`

Explanation:

We have the two equations as,

3a+b=225 and b=a-15

So in the substitution involved here its better if we substitute the second equation into first one.

We have the term b=a-15 so on directly substituting we get

4a=240,

a=60.

hence b would be 45.

In this way its better to substitute second one in the first one giving the following,

`3a+a-15=225`