giúp tôi nhanh với trưa nay là tôi phải làm rồi
a) 5x(10x+7)-25x(2x-3) = 40
50x2+35x-50x2+75x = 40
(50x2-50x2)+(35x+75x) = 40
110x = 40
x =\(\dfrac{40}{110}\)=\(\dfrac{4}{11}\)
b)
Bài 1:
a: \(\Leftrightarrow50x^2+35x-50x^2+75x=40\)
=>110x=40
=>x=4/11
b: \(\Leftrightarrow3x^2-6x+2x-4-x^2+4x-3=4\)
=>2x^2-7=4
=>2x^2=11
=>x^2=11/2
hay \(x=\pm\sqrt{\dfrac{11}{2}}\)
Bài 2:
a: \(=x+2ax-2ay-y\)
\(=x\left(1+2a\right)-y\left(2a+1\right)=\left(2a+1\right)\left(x-y\right)\)
b: \(=5a\left(a-x\right)-7\left(a-x\right)=\left(a-x\right)\left(5a-7\right)\)
