2x+5(x-2)=7,x=2^2

解答

2 x + 5 (x - 2) = 7, x = 2^{2}

无解

求解步骤

[2 x + 5 (x - 2) = 7 x = 2^{2}]

替代

x = 2^{2}

[2 \cdot 2^{2} + 5 (2^{2} - 2) = 7]

化简

[18 = 7]

18 = 7

为假，因此方程组没有解

无解

2 x + y = 4, 3 x + z = 6, 2 y + z = 7 x + y + z

6 r - 5 t = - 11, 7 t - 8 r = 15

2 x + 3 y = 5, 3 x + 4 y = 7

x + 2 y + z = 2, - y + z = - 3

x - y = 1, x - 3 y = - 3