how to factorize? thanks?
回答 (2)
2015-12-22 3:52 am
5(3x+y)^2+6(3x+y)-8
let u=3x+y
factors of -40 that add to 6: 10 & -4
5u^2+6u-8
5u^2 + 10u - 4u - 8
5u(u+2) - 4(u+2)
(5u-4)(u+2)
(5(3x+y)-4)(3x+y+2)
(15x+5y-4)(3x+y+2)
let u=3x+y
factors of -40 that add to 6: 10 & -4
5u^2+6u-8
5u^2 + 10u - 4u - 8
5u(u+2) - 4(u+2)
(5u-4)(u+2)
(5(3x+y)-4)(3x+y+2)
(15x+5y-4)(3x+y+2)
2015-12-22 3:45 am
This is a quadratic in (3x + y).
So let u = 3x + y, and you get
5u^2 + 6u - 8. Then just factor
that, then substitute back.
So let u = 3x + y, and you get
5u^2 + 6u - 8. Then just factor
that, then substitute back.
收錄日期: 2021-05-01 20:42:10
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