Question

Mai and Jada are solving the equation 2x2 - 7x = 15 using the quadratic formula but found different solutions. Jada wrote: x X Mai wrote: -7 +172 – 4(2)(-15) 2(2) -7 +49-(-120) 4 -7 + 169 4 -7 + 13 X 4 3 = -5 or x = 2 -(-7)+/-72 - 4(2)(-15) 2(2) 7+1-49-(-120) 4 7+771 x х x 4 х Do you agree with either of them? Explain your reasoning.

Answer 1

$\text{ 2x}^2\text{ - 7x = 15}$

Both students are wrong

Mai is wrong because doesn't change the sign of "b" on the first step.

Jada is wrong because doesn't change the sign of "b" inside the square root.

Both signs are positive and they wrote them as negative.