Question

YOU BE THE TEACHER Your friend solves the equation 9x2 = 36. Is your friend correct? 9x2 = 36 x = 4 x= 14 x= +2 O yes O no Explain your reasoning.

Answer 1

ANSWER

Yes

EXPLANATION

Your friend is correct.

First he divided both sides by 9: 36 divided by 9 is 4

Then he did the square root, which has two results: one positive and one negative. This gives +2 and -2.

Another way to check the result is to replace it into the equation. If the equation is true, then the result is correct:

$\begin{gathered} 9(2)^2=36 \\ 9\cdot4=36 \\ 36=36\text{ }\rightarrow\text{ true} \\ \\ 9(-2)^2=36 \\ 9\cdot4=36 \\ 36=36\text{ }\rightarrow\text{ true} \end{gathered}$