Don’t depend on backsolving too much. There are lots of math questions that
can’t be backsolved at all. And most that can be backsolved are almost
certainly more quickly solved by a more direct approach.
BACKSOLVE
One of the answer choices has to be correct, so you can just try them
out. Since the answer choices are generally in numerical order, start
with (B) or (D). If it doesn’t work, you at least know whether you’re
looking for something bigger or something smaller. At most, you only
have to try the middle number of the remaining three choices.Note: You don’t always have to try all the answer choices when
backsolving.QUADRATIC EQUATIONS
To solve a quadratic equation, put it in the “ax^2 + bx + c = 0” form, factor the
left side (if you can), and set each factor equal to 0 separately to get the two
solutions. To solve x^2 + 12 = 7x, first rewrite it as x^2 – 7x + 12 = 0. Then factor
the left side: