Below is a question from a recent SAT exam. It is a non-calculator question that would typically take a student 1-2 minutes to complete.
What are all the values of x that satisfy the equation above?
(D) –3 and –1
To solve this equation, we need to factorise the top of the fraction. We do this with a method known as the difference of two squares. As and 1 are both square numbers the top of the fraction becomes two brackets containing + and – the square roots of and 1
We can now simplify this fraction as x-1 appears on the top and bottom of the fraction.
We now solve.
Copyright 2021 Forbest Academy 福拜思教育