If one factor of 3x^2 + 15x + 12 = 0 is (x + 4), which is another factor?
A) 3
B) x + 1
C) Both A and B
D) Neither A nor B
2007-06-01 02:45:23 · 6 answers · asked by Anonymous in Science & Mathematics ➔ Mathematics
3 is clearly a factor as 3x^2, 15x and 12 are all divisible by 3
3x^2+15x+12
= 3(x^2+5x+4)
= 3(x+1)(x+4)
Both 3 and (x+1) are factors and so the answer is C
2007-06-01 02:48:58 · answer #1 · answered by gudspeling 7 · 0⤊ 0⤋
B
(3x+3)(x+4)=3x^2+15x+12
(3x+3) simplifies to (x+1)
2007-06-01 09:54:27 · answer #2 · answered by vector4tfc 4 · 0⤊ 0⤋
Well, since every term is divisible by there, A is one root, and D cannot possibly be true.
Divide out the 3 and you get x^2 + 5x + 4 = 0
Possible roots of 4 are 1,4 2,2, -1,-4 -2,-2
It should be easy to see that 1 + 4 = 5, so
(x + 1)(x + 4) = 0
So B is also a factor, and the answer is C.
2007-06-01 09:50:04 · answer #3 · answered by TychaBrahe 7 · 0⤊ 0⤋
3x^2+15x+12=0
3(x^2+5x+4)=0
3(x+1)(x+4) = 0
C Both A and B
Am I helping you with your exam?
2007-06-01 09:49:54 · answer #4 · answered by nmhawthorne 1 · 0⤊ 0⤋
D
All others are impossible
2007-06-01 09:48:35 · answer #5 · answered by Ben 2 · 0⤊ 2⤋
Neither.
The other two won't work.
2007-06-01 09:49:04 · answer #6 · answered by Vehicle 3 · 0⤊ 1⤋