x=ay

y=x+10

plugging it in x= a(x+10)

the book SAYS solving for x yields x= 10a/(1-a)

for the life of me I can't see how they got that.

I tried multiplying by its reciprocal, working around it.... I just cant see it for the life of me.

the book's solution doesn't show this step. is there something really basic I'm overlooking?