1.
2x(x-5) - (x+3)(x-2)
= 2x² - 10x - (x² + x - 6)
= x² - 11x + 6
2.
(-3xy²)² × (-xy)^3
= 9x²y^4 × (-x^3y^3)
= -9(x^5)(y^7)
3.
(1/9)^(-1) + (-2)^3 + 3 - (1-π)º
= 9 -8 + 3 - 1
= 3
4.
(2x-1)²+(1-3x)²=13(x-1)(x+1)
展开得：
(4x² - 4x + 1) + (9x² - 6x + 1) = 13(x² - 1)
即13x² - 10x + 2 = 13x² - 13
所以10x = 15
解得x = 1.5
5.
(x-y)²
= x² + y² - 2xy
= (x+y)² - 4xy
= 36 - 8 = 28
希望有用.
楼上的都有马虎.