The intercept form is [tex]y=a(x-p)(x-q)[/tex] where p, q - the zeroes of a function.
1.
[tex]y=2x^2-4x \\
y=2x(x-2) \\
y=2(x-0)(x-2) \\
\hbox{the zeroes - }\boxed{x=0 \ and \ x=2}[/tex]
2.
[tex]y=2x^2-11x-21 \\
y=2x^2-14x+3x-21 \\
y=2x(x-7)+3(x-7) \\
y=(2x+3)(x-7) \\
y=2(x+\frac{3}{2})(x-7) \\ y=2(x-(-\frac{3}{2}))(x-7) \\
\hbox{the zeroes - }\boxed{x=-\frac{3}{2} \ and \ x=7}[/tex]
