I think B. Would be the answer
I've done the first four questions. Use this method to answer the rest. For an odd number of objects find the cost of one and multiply by how many you are asked to find.
Answer:
I can't see Mathieu's work but I will show the right steps and maybe you can find where Mathieu went wrong.
f(x)=x^2+4x+3
f(x)=(x+3)(x+1) Since 3*1=3 and 3+1=4
The x-intercepts can be found by setting y to 0 and solving for x
(in other words replace that f(x) thing with 0 and solve for x)
0=(x+3)(x+1)
Now set both factors equal to 0
x+3=0 or x+1=0
x =-3 x=-1
The x-intercepts are at (-3,0) and (-1,0)