展开 (4-5x+2x^2)(1+x,1-x,x^2)

解答

展开

(4 - 5 x + 2 x^{2}) (1 + x, 1 - x, x^{2})

4 \cdot 1 + 4 x, 1 - 4 x, x^{2} - 5 \cdot 1 \cdot x - 5 xx, 1 + 5 xx, x^{2} + 2 \cdot 1 \cdot x^{2} + 2 x^{2} x, 1 - 2 x^{2} x, x^{2}

求解步骤

(4 - 5 x + 2 x^{2}) (1 + x, 1 - x, x^{2})

= (4 - 5 x + 2 x^{2}) (1 + 1, x -, x^{2} x)

打开括号

= 4 \cdot 1 + 4 x, 1 + 4 (- x, x^{2}) + (- 5 x) \cdot 1 + (- 5 x) x, 1 + (- 5 x) (- x, x^{2}) + 2 x^{2} \cdot 1 + 2 x^{2} x, 1 + 2 x^{2} (- x, x^{2})

使用加减运算法则

+ (- a) = - a, (- a) (- b) = ab

= 4 \cdot 1 + 4 x, 1 - 4 x, x^{2} - 5 \cdot 1 \cdot x - 5 xx, 1 + 5 xx, x^{2} + 2 \cdot 1 \cdot x^{2} + 2 x^{2} x, 1 - 2 x^{2} x, x^{2}

e x p an d ((5 x + 2) \cdot (x + 9)) \cdot x

e x p an d ln (x^{9} + 6)

e x p an d (x^{2} + x + 4) d x

e x p an d 81 \cdot 79

e x p an d (\frac{1 - s t}{2}) K