Question

Các bn giúp mih lm bài nha 

a) x² + 3x + 2

b) -x² + x + 2

c) 7x² - 12

d) -6x² - x + 1

e) 10x² + 7x + 1

j) -5x² + 4x + 1

g) -x² - x + 12

h) -4x² + 12x - 5

k) 4x² + 4x + 1

l) -6x² -x + 2

Answer 1

a)\(x^2+3x+2\)

\(=x^2+x+2x+2\)

\(=x\left(x+1\right)+2\left(x+1\right)\)

\(=\left(x+2\right)\left(x+1\right)\)

Answer 2

k)\(4x^2+4x+1\)

\(=\left(2x\right)^2+2.2x+1^2\)

\(=\left(2x+1\right)^2\)

Answer 3

j) \(-5x^2+4x+1\)

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

\(=-5x\left(x-1\right)-\left(x-1\right)\)

\(=\left(-5x-1\right)\left(x-1\right)\)

Answer 4

e) \(10x^2+7x+1\)

\(=10x^2+5x+2x+1\)

\(=5x\left(2x+1\right)+2x+1\)

\(=\left(5x+1\right)\left(2x+1\right)\)

Answer 5

c) \(7x^2-12\)

\(=\left(\sqrt{7}x\right)^2-\left(\sqrt{12}\right)^2\)

\(=\left(\sqrt{7}x+\sqrt{12}\right)\left(\sqrt{7}x-\sqrt{12}\right)\)

Answer 6

h) \(-4x^2+12x-5\)

\(=-4x^2+10x+2x-5\)

\(=-2x\left(2x-5\right)+\left(2x-5\right)\)

\(=\left(1-2x\right)\left(2x-5\right)\)

Answer 7

d) \(-6x^2-x+1\)

\(=-6x^2+3x-2x+1\)

\(=-3x\left(2x-1\right)-\left(2x-1\right)\)

\(=\left(-3x-1\right)\left(2x-1\right)\)

Answer 8

\(-6x^2-x+2\)

\(=-6x^2-4x+3x+2\)

\(=-2x\left(3x+2\right)+3x+2\)

\(=\left(1-2x\right)\left(3x+2\right)\)

Answer 9

g) \(-x^2-x+12\)

\(=-x^2-3x+4x+12\)

\(=-x\left(x+3\right)+4\left(x+3\right)\)

\(=\left(4-x\right)\left(x+3\right)\)

Answer 10

b) \(-x^2+x+2\)

\(=-x^2+2x-x+2\)

\(=-x\left(x-2\right)-\left(x-2\right)\)

\(=\left(-x-1\right)\left(x-2\right)\)