Question

a(x+6)+x(x-3a)=9 при x=2a-3

Answer 1

ax+6a+x²-3ax=-2ax+6a+x²

Answer 2

а(x+6)+x(x-3a)=9
ax+6a+x²-3ax=9
x²-2ax+6a=9
(2a-3)²-2a*(2a-3)+6(2a-3)=9
4a²-12a+9-4a²+6a+12a-18-9=0
6a-18=0
6a=18
a=6