2. a. 3/4x-1/3=-5/6⇔3/4x=-5/6+1/3⇔3/4x=-1/2⇔x=-1/2:3/4⇔x=-2/3
b. ⇔4/27-4/3x=-2/9⇔4/3x=4/27-(-2/9)⇔4/3x=10/27⇔x=10/27:4/3⇔x=5/18
c. ⇔(1/4-x)²-5/4=29/16⇔(1/4-x)²=29/16+5/4⇔(1/4-x)²=49/16
TH1:⇔(1/4-x)²=(7/4)²⇔1/4-x=7/4⇔x=1/4-7/4⇔x=-3/2
TH2:⇔(1/4-x)²=(-7/4)²⇔1/4-x=-7/4⇔x=1/4-(-7/4)⇔x=2
3.a. CR là: 30 . 3/5 = 18 (m)
S là: 30 . 18 = 540(m²)
b. S trồng rau: 540 . 9/20 = 243(m²)
S trồng hoa: 81 : 100 . 75 = 108(m²)
S đào hoa nuôi cá: 540 - (243 + 108) = 189(m²)
S đào hoa nuôi cá chiếm số % S cả mảnh đất: (189 : 540 . 100)% = 35%
