展开 (4x+7y=3,7)(3x-y=16)

解答

展开

(4 x + 7 y = 3, 7) (3 x - y = 16)

12 x^{2} - 4 x y = 16

求解步骤

(4 x + 7 y = 3, 7) (3 x - y = 16)

= (4 x + 7 \cdot 3 \cdot 7 =, y) (3 x - 16 = y)

使用 FOIL 方法:

(a + b) (c + d) = a c + a d + b c + b d

a = 4 x, b = 7 y = 3, 7, c = 3 x, d = - y = 16

4 x \cdot 3 x + 4 x (- y = 16) + 7 y = 3, 7 \cdot 3 x + 7 y = 3, 7 (- y = 16)

使用加减运算法则

+ (- a) = - a

4 \cdot 3 xx - 4 x y = 16 + 7 y = 3, 7 \cdot 3 x - 7 y = 3, 7 y = 16

乘开

4 \cdot 3 xx - 4 x y : 12 x^{2} - 4 x y

12 x^{2} - 4 x y = 16

e x p an d [x (x + 1)]^{2}

e x p an d 3 x (3 x + 2 x ln (x))

e x p an d x \cdot 6 x

e x p an d \frac{( 2 a - b ) ^{2}}{9}

e x p an d \frac{2 ( d - 2 )}{5}