解方程x(3x-4)+2x(x+7)=5x(x-7)+90,
去括号得:3x2-4x+2x2+14x=5x2-35x+90,
移项合并、得:45x=90,
系数化为1得:x=2.
故选B.
若x(3x-4)+2x(x+7)=5x(x-7)+90,则x等于( ) A.-2 B.2 C.-12 D.12
若x(3x-4)+2x(x+7)=5x(x-7)+90,则x等于( )
A. -2
B. 2
C. -
D.
A. -2
B. 2
C. -
1 |
2 |
D.
1 |
2 |
数学人气:569 ℃时间:2020-02-06 06:13:37
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