Question

Find the zeros of the function: f(x) = x2 -7x + 12 Write your answer like this example: x=2,3 with no spaces.

Answer 1

Whenever a quadratic equation is in the form

$x^2-sx+p$

(i.e. the leading terms is 1), you can solve it by looking for two numbers that give $s$ when summed and $p$ when multiplied.

So, in your case,

$x^2-sx+p = x^2-7x+12 \iff s = 7,\quad p=12$

So, we're looking for two numbers $x_1,\ x_2$ such that:

$x_1+x_2 =7,\quad x_1x_2=12$

you can clearly check that these numbers are 3 and 4.