Find $a$ and $b$ for the following equation: $x^2 - 10x + a = (x + b)^2$

Question

I'm starting A Level Maths and I've encountered this equation, which I have not seen at GCSE. I have tried to search for it on the web but I'm not sure how to phrase it, so here goes:

How would I:

Find $a$ and $b$ in the following equation:

$$x^2 - 10x + a = (x + b)^2$$

I know the answer is $a = 25, b = -5$. I am not sure what the process is.

Thanks in advance

Answer 1

$$(x+b)^2=x^2+2bx+b^2$$

Comparing with $$x^2-10x+a,$$

You should be able to determine $a$ and $b$.