Question

Giúp mình với

x²+8x+7

x²-5x+6

x²+3x-18

3x² -16x+18

Answer 1

x² + 8x + 7  = x² + x + 7x + 7 = x(x + 1) + 7(x + 1)= (x + 7)(x + 1)

x² - 5x + 6 = x² - 2x - 3x + 6 = x(x - 2) - 3(x - 2) = (x - 3)(x - 2)

x² + 3x  - 18 = x² + 6x - 3x - 18 = x(x + 6) - 3(x + 6) = ((x - 3)(x + 6)

Answer 2

\(a,x^2+8x+7=x^2+7x+x+7=x\left(x+7\right)+\left(x+7\right)=\left(x+7\right)\left(x+1\right).\)

\(b,x^2-5x+6=x^2-2x-3x+6=x\left(x-2\right)-3\left(x-2\right)=\left(x-2\right)\left(x-3\right)\)

\(c,x^2+3x-18=x^2+6x-3x-18=x\left(x+6\right)-3\left(x+6\right)=\left(x+6\right)\left(x-3\right)\)

\(d,3x^2-16x+18=3x^2-4x-12x+18\)

Answer 3

trả lời

x^2+8x+7=(x+1)(x+7)

x^2-5x+6=(x-2)(x-3)

x^2+3x-18=(x-3)(x+6)

Answer 4

\(x^2+8x+7\)

\(=x^2+7x+x+1\)

\(=\left(x^2+7x\right)+\left(x+1\right)\)

\(=x\left(x+7\right)+\left(x+7\right)\)

\(=\left(x+7\right)\left(x+1\right)\)

Answer 5

\(x^2-5x+6\)

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

\(=\left(x^2-2x\right)-\left(3x-6\right)\)

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

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

Answer 6

\(x^2+3x-18\)

\(=x^2+6x-3x-18\)

\(=\left(x^2+6x\right)-\left(3x+18\right)\)

\(=x\left(x+6\right)-3\left(x+6\right)\)

\(=\left(x-3\right)\left(x+6\right)\)

Answer 7

\(3x^2-16x+18=3x^2-4x-12x+18=3x^2-2x-14x+18=......\)

Mk nghĩ câu này bị sai đề hay sao á .

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