a)7x2 + 6x - 13
= 7x2 - 7x + 13x - 13
= (7x2 - 7x) + (13x - 13)
= 7x(x - 1) + 13(x - 1)
= (7x + 13)(x - 1)
b) 15(x - y) - 25x + 25y
= 15(x - y) - (25x - 25y)
= 15(x - y) - 25(x - y)
= (15 - 25)(x - y)
= -10(x - y)
c) 36 - 4a2 + 20ab - 25b2
= 36 - (4a2 - 20ab + 25b2)
= 62 - (2a - 5b)2
= (6 - 2a + 5b)(6 + 2a - 5b)
= (5b - 2a + 6)(2a - 5b + 6)
nhớ tik mik nha
. Ak có j ko hiểu thì cứ bình luận ở dưới mik giải cho
a, \(7x^2+6x-13\)
=\(7x^2-7x+13x-13\)
=\(\left(7x^2-7x\right)+\left(13x-13\right)\)
=\(7x\left(x-1\right)+13\left(x-1\right)\)
=\(\left(x-1\right)\left(7x+13\right)\)
b, \(15\left(x-y\right)-25x+25y=15\left(x-y\right)-\left(25x-25y\right)\)
=\(15\left(x-y\right)-25\left(x-y\right)=\left(x-y\right)\left(15-25\right)\)
=(x-y).-10
