10x^3 – 14x^2 – 5x + 7 =
2007-08-25 12:12:25 · 5 answers · asked by snickernikki727 1 in Science & Mathematics ➔ Mathematics
I am going to work the problem. Please help me further understand...
10x^3 – 14x^2 – 5x + 7 =
(5x-7)-(5x+7)
This is what I get, where am I going wrong?
2007-08-26 03:24:15 · update #1
10x ³ - 14x ² - 5x + 7
(2 x ²) (5x - 7) - (5x - 7)
(5 x - 7) (2 x ² - 1)
(5x - 7) (√2 x - 1) (√2 x + 1)
2007-08-29 11:01:41 · answer #1 · answered by Como 7 · 0⤊ 0⤋
Okay when I work these problems I look for things in common. I see a term with 14 and 7 and I see one with 5 and 10. So I am going to group those together and take out what I can and see what's left.
working with just the 14 and 7 terms ( don't forget to carry along any - 's)
-14x^2 + 7 I see I can pull out a -7
so this turns into -7 ( 2x^2 - 1)
okay now the others....
10x^3 -5x In can pull out 5x from this one
5x (2x^2 -1)
now put these back together (remember it's +)
5x (2x^2 -1) -7 ( 2x^2 - 1)
now notice how they both have the 2x^2-1 in common. I can factor that out....and in the other parenthesis just put what's left....
(2x^2 - 1) (5x - 7)
And that is factoring by grouping.
2007-08-25 19:22:37 · answer #2 · answered by Anonymous · 1⤊ 0⤋
In these problems, it seems like it is always that the first two terms contain the second two terms.
You can see that (5x - 7) can come out of the first two terms, to get:
2x^2(5x - 7) - (5x - 7)
Then factor out the (5x - 7) from this expression:
(5x - 7)(2x^2 - 1), which is the final answer.
2007-08-25 19:18:32 · answer #3 · answered by Anonymous · 1⤊ 0⤋
10x^3 – 14x^2 – 5x + 7
= 2x^2(5x-7)-(5x-7)
= (2x^2-1)(5x-7)
2007-08-25 19:18:57 · answer #4 · answered by sahsjing 7 · 1⤊ 0⤋
10x^3 - 5x - 14x^2 + 7
5x(2x^2 - 1) -7(2x^2 - 1)
= (5x - 7)(2x^2 - 1)
2007-08-25 19:19:30 · answer #5 · answered by Anonymous · 1⤊ 0⤋