Im supposed to factor them by the grouping method but i cant figure it out
2007-10-15 11:35:18 · 2 answers · asked by Patricia M 1 in Science & Mathematics ➔ Mathematics
PROBLEM 1:
3x² - 2xy - 6x + 4y
Let's group the terms involving just x together:
3x² - 6x - 2xy + 4y
Now factor out a 3x from the first 2 terms:
3x(x - 2) - 2xy + 4y
And factor out a 2y from the last 2 terms:
3x(x - 2) - 2y(x - 2)
Ah! You have a common x-2 you can factor out:
(3x - 2y)(x - 2)
PROBLEM 2:
3x^3-15x²-18x
Well, it's pretty obvious that you have a common 3x factor in each term:
3x(x² - 5x - 6)
And inside the parentheses you can use standard factoring:
3x(x - 6)(x + 1)
2007-10-15 11:41:06 · answer #1 · answered by Puzzling 7 · 0⤊ 0⤋
3x^2 - 2xy - 6x + 4y
x(3x - 2y) - 2(3x - 2y) {grouping}
(x - 2)(3x - 2y)
The hard part is seeing that - 6x + 4y = -2(3x - 2y)
3x^3 - 15x^2 - 18x
3x(x^2 - 5x - 6) {common factor}
3x(x - 6)(x + 1)
2007-10-15 18:41:24 · answer #2 · answered by kindricko 7 · 0⤊ 0⤋