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.

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

Step-by-step 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

b.) 160 miles on a 5 gallons car

step-by-step explanation:

240/10=24 miles/gallon

160/5=32 miles/gallon

30/1=30 miles/gallon

168/6= 28 miles/gallon

32 miles/gallon is the most amount, so this is the best.