(内江)(本小题满分7分)计算:.
化简:5(2x―7y)―3(4x―10y)
计算:(4b-3ab)+(-5b+3ab)
先化简,再求值:当x=时,求多项式2x2-5x+x2+4x―3x2―2的值
① (-7)×(-5)+(-10)÷2②(+)×12
① 3-4+6-7② 18-6÷(-2)×()