Question

Factor completely 3x2 + 2x – 1. (3x + 1)(x - 1) (3x + 1)(x + 1) (3x - 1)(x + 1) (3x - 1)(x - 1)

Answer 1

So for this question you know you factor it into binomials because of the answer options. So the values of the equation to factor can help determine the answer. So looking at the constant in the function, the two numbers must multiply together to make -1, meaning there is a positive and negative number. which options does this rule out?

Answer 2

a and d?

Answer 3

as the answers that are ruled out?

Answer 4

yes

Answer 5

not quite. the function shows that because the constant term is negative, one of the constants in the factored terms must be negative and one must be positive, so a and d are the answers that may be correct. Do you understand why?

Answer 6

now i do

Answer 7

ok. So now we can examine the b values. Because this value is a positive, the numbers that are added together have to add to be positive. The 3x must multiply to apositive number and the x to a negative, so that when they are added it creates a negative. Any confusion?

Answer 8

I understand

Answer 9

ok so the two binomials we are looking for will have a 3x and a positive 1 in separate binomials. Which answer is this?

Answer 10

c

Answer 11

That's correct :)

Answer 12

thank you

Answer 13

no problem :)