Question

Percy solved the equation x2 + 7x + 12 = 12. His work is shown below. Is Percy correct? Explain.

1. (x + 3)(x + 4) = 12

2. x + 3 = 12 or x + 4 = 12

3. x = 9 or x = 8

Answer 1

Percy is incorrect

Explanation:

I plugged in 9 and 8 for x and both of them did NOT solve it. The only number I know of that can solve it is -7. -7^2=49

-7 multiplied by 7 =-49

(49) + (-49) + 12 = 12

Answer 2

Percy was not correct.

Percy did not write the equation in standard form before factoring.

The correct solutions are 0 and –7.

The equation should have first been written as x2 + 7x = 0 before factoring.

The solutions 8 and 9 do not make the equation true.

Explanation: