Question

Mathieu is finding the x-intercepts of the function

f(x) = x2 + 4x + 3. His work is shown below.

0 = x2 + 4x + 3
0 = (x + 3)(x + 1)
x + 3 = x + 1
x = x – 2
0 = –2
There are no x-intercepts.
Which error did Mathieu make?

He factored incorrectly.
He did not use the constant as the x-intercept.
He set the factored expressions equal to each other.
He incorrectly solved the equation x + 3 = x + 1.

Answer 1

c

Explanation:

Answer 2

He set the factored expressions equal to each other. instead of setting them equal to zero

Explanation:

f(x) = x^2 + 4x + 3. His work is shown below.

0 = x^2 + 4x + 3

0 = (x + 3)(x + 1)

Here is where we use the zero product property

x+3 = 0 x+1 =0 We do not set them equal to each other