Question

(x-1)(x+3)=12

Answer 1

\[x ^{2}+3x-x-3=12\]
\[x ^{2}+2x-15=0\]
\[(x-3)(x+5)=0\]
Therefore
\[ 0=x-3\]
\[ x=3\]
and
\[ 0=x+5\]
\[ x=-5\]