CAI NAY DE NHUNG HOI DAI TOI CO THE HUONG DAN BN DC
BAI 2O
B1 TIM MSC.
B2 KHU MAU
B3 GPT
VD Y a bai 20
msc=30
$\frac{(x-3).6}{30}$ =$\frac{5.6}{30}$ -$\frac{(1-2x)10}{30}$ <=> 6x-18=30-10+20x <=>-14x=38 <=>x≈-2,7
bai21
de x xd thi x∦0
tim tung bai ra ok baibai