几乘几等于700?(40—2x)(28—2x)=364,x等于几?
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几乘几等于700?(40—2x)(28—2x)=364,x等于几?
![几乘几等于700?(40—2x)(28—2x)=364,x等于几?](/uploads/image/z/18005413-13-3.jpg?t=%E5%87%A0%E4%B9%98%E5%87%A0%E7%AD%89%E4%BA%8E700%3F%EF%BC%8840%E2%80%942x%EF%BC%89%EF%BC%8828%E2%80%942x%EF%BC%89%EF%BC%9D364%2Cx%E7%AD%89%E4%BA%8E%E5%87%A0%3F)
100*7=700
(40—2x)(28—2x)=364
4(20-x)(14-x)=364
X^2-34x+280-91=0
(x-27)(x-7)=0
x=27 ,x=7
(40—2x)(28—2x)=364
4(20-x)(14-x)=364
X^2-34x+280-91=0
(x-27)(x-7)=0
x=27 ,x=7