Question

bài 1: phân tích thành nhân tử

a) x²+5x-6

b) 7x-6x²-2

c) x²+4x+3

d) 2x²+3x-5

e) 16x-5x²-3

Answer 1

a) x² + 5x - 6
= x² - x + 6x - 6
= x(x - 1) + 6(x - 1)
= (x - 1)(x + 6)

Answer 2

c) x² + 4x + 3

= x² - 3x - x + 3

= (x² - 3x) - (x - 3)

= x(x - 3) - (x - 3)

= (x - 3) - (x - 1)

Answer 3

d) 2x² + 3x - 5

= 2x² + 5x - 2x - 5

= (2x² - 2x) + (5x - 5)

= 2x(x - 1) + 5(x - 1)

= (x - 1) + (2x + 5)

Answer 4

e) 16x - 5x² - 3

= - (5x² - 16x + 3)

= - (5x² - x - 15x + 3)

= - [x(5x - 1) - 3(5x - 1)]

= - [(5x - 1)(x - 3)]

= - (5x - 1)(x - 3)

Answer 5

a, x²+5x-6

=x²-x+6x-6

=x(x-1)+6(x-1)

=(x-1)(x+6)

b, 7x-6x²-2

=-6x²+7x-2

=-6x²+4x+3x-2

=-2x(3x-2)+(3x-2)

=(3x-2)(-2x+1)

c, x²+4x+3

=x²+x+3x+3

=x(x+1)+3(x+1)

=(x+1)(x+3)

d, 2x²+3x-5

=2x²-2x+5x-5

=2x(x-1)+5(x-1)

=(x-1)(2x+5)

e, 16x-5x²-3

=-5x²+16x-3

=-5x²+15x+x-3

=-5x(x-3)+(x-3)

=(x-3)(-5x+1)

Answer 6

b) 7x - 6x² - 2

= - (6x² - 7x + 2)

= - (6x² - 3x - 4x + 2)

= - [3x(2x - 1) - 2(2x - 1)]

= - (2x-1) - (3x - 2)