Question

Given : ab = 8a b + d = 20 Prove : d = 12

Answer 1

We have:

`ab=8a(1)`
`b+d=20(2)`

In order to prove that d=12, we do as follows:

`ab=8a\Rightarrow b=(8a)/(a)\Rightarrow b=8(3)`

Now, replacing (3) on (2), we have:

`8+d=20\Rightarrow d=20-8\Rightarrow d=12(4)`

And is proven that d=12.