Question

Can somebody help me????

Answer 1

`f(x)=5x^2-3\\\\\\ f(x+a)=5(x+a)^2-3=5(x^2+2ax+a^2)-3=\\\\=\boxed{5x^2+10ax+5a^2-3}`

On the other hand:


`f(x+a)=5x^2+30x+42`

so:


`10ax=30x\\\\10a=30\qquad|:10\\\\\boxed{a=3}`

Answer C.