Question

Tìm x, biết: a. (2x - 1)² - (5x - 5)² = 0 b. (2x + 1)² - 4(x + 3)² = 0

Answer 1

a)

(2x-1)²-(5x-5)²=0

<=>(2x-1-5x+5)(2x-1+5x-5)=0

<=>(-3x+4)(7x-6)=0

<=>\(\orbr{\begin{cases}-3x+4=0\\7x-6=0\end{cases}}\)

<=>\(\orbr{\begin{cases}-3x=-4\\7x=6\end{cases}}\)

<=>\(\orbr{\begin{cases}x=\frac{-4}{-3}=\frac{4}{3}\\x=\frac{6}{7}\end{cases}}\)

Answer 2

b)

(2x+1)²-4(x+3)²=0

<=>(2x+1)²-[2(x+3)]²=0

<=>(2x+1)²-(2x+6)²=0

<=>(2x+1-2x-6)(2x+1+2x+6)=0

<=>-5(4x+7)=0

<=>4x+7=0

<=>4x=-7

<=>\(x=-\frac{7}{4}\)

Answer 3

Làm ơn làm phước giúp tui, tui cần gấp :(((