Question

The square of a number I see equal to two less than three times the number. What are two possible values of the number? A. 1,2 B. -1,2 C. 1,-2 D. -1,-2 E. 2,3

Answer 1

Option A

Explanation:

Let us take this number as x, translating this description of the equation into mathematical language;

`x^2 = 3x - 2`

Now let us solve for x;

`x^2 = 3x - 2,\\x^2+2=3x-2+2,\\x^2+2=3x,\\x^2+2-3x=3x-3x,\\x^2-3x+2=0,\\\\Factored = \left(x-1\right)\left(x-2\right)=0,\\Zero Factor Principle, \\x = 1, x = 2\\\\Solution - Option A`

* Note that for the the previous problem I solved, I set up a similar equation that had two values for the width, one negative and the other positive. Now the width could only be a positive number, so there was only one solution out of the two.