Question

(2x - 1)(x + 3) = x^2 - 3

Answer 1

You should start by opening the parenthesis, and then adding like terms together:
\[2x^2+6x-x-3=x^2-3 \implies 2x^2+5x-1=x^2-3 \implies x^2+5x=0\]
Take x as a common factor:
\[x(x+5)=0 \implies x=0, x=-5\]
That's x is either 0 or -5