第66页

信息发布者:
D
减$2x$
$-1$
等式基本性质1
乘$-3$
$-6$
等式基本性质2
解:$x - 9 + 9 = 6 + 9$
$x = 15$
解:$-0.2x \div (-0.2) = 10 \div (-0.2)$
$x = -50$
解:$3 - \frac{1}{3}x + \frac{1}{3}x - 2 = 2 + \frac{1}{3}x - 2$
$\frac{1}{3}x \times 3 = 1 \times 3$
$x = 3$
解:$-2x + 1 - 1 = 0 - 1$
$-2x \div (-2) = -1 \div (-2)$
$x = \frac{1}{2}$
(1)$(1-10\%)a=\frac{1}{2}a+80$
(2)$4n+5m=4.9$
(3)$150\times0.8 - m = b$
(4)$100x + 80x = 480$
解: (1)长为x+2 容积为x(x+2) (2)x(x+2)=15