20× 1.2+(x-20)×2=56
24+2x-40=56
2x=-24+40+56
2x=72
x=36
Her family used 36 tons of water this month.
2. If the price is reduced by X billion yuan in 2004, the price will be reduced by 6 billion yuan in 2007.
54+x+35+40+6x=269
7x= 140
x=20
In 2004 and 2007, the amount of drug price reduction was 2 billion yuan and 654.38+0.2 billion yuan respectively.
3.①3x-2=5 3x=5+2 3x=7 x=7/3
②6-3(x+ 1/2)= 1 6-3x-3/2 = 1-3x =-6+3/2+ 1-3x =-7/2 x = 7/6
4.a plans to process X parts, and B plans to process 420-x parts.
x( 1+ 1 1%)+(420-x)( 1+8%)= 420×( 1+ 10%)
x=280
Party A and Party B each plan to process 280 140 parts.
5.①-2x+3=6-5x x= 1
②7/3x+ 1 = 1/3(x-3)7x+3 = x-3 x =- 1
③x-2/3-3x+ 1/6 = 1-2x = 3/2x =-3/4
④4(2y- 1)-2(5y+ 1/2)= 3 8y-4- 10y- 1 = 3-2y = 8y =-4
6.①y 1 = y2 5x-3/2 = 3x+4/6 x = 13/ 12
②(5x-3/2)-(3x+4/6)= 3 x = 3 1/ 12