Question 630740
well,...
you butchered the problem statement so i had to look elsewhere to see what it really was.
the problem is:
megan factored the expression 35x^2 - 38x + 8 and got (5x-2) * (7x-4).
when jacob applied the foil principle, he got 35x^2 - 34x + 8.
what's wrong?
if you use the foil principle to multiply (5x-2) * (7x-4), you will get:
35x^2 - 34x + 8
you are correct there.
if you factor 35x^2 - 38x + 8 yourself, you should find that the factors are:
(5x - 4) * (7x - 2)
when you multiply these factors out, you get:
35x^2 - 38x + 8
this is the correct answer.
megan got the right number to use but she put them in the wrong place.
5x and 7x were correct.
-4 and -2 were correct.
she just placed them wrong.
if you look at the original equation, you will see that:
-2 * -4 = 8
5 * 7 = 35
5*-2 + 7*-4 = -10 + -28 = -38
but........
5*-4 + 7*-2 = -20 + - 14 = -34
bad factors are:
(5x - 2) and (7x - 4)
good factors are:
(5x - 4) and (7x - 2)