Question

`l) 4(2x + 7)^2= 9(x + 3)^2`

Giải pt

Answer 1

\(\Leftrightarrow\left(4x+14\right)^2=\left(3x+9\right)^2\)

\(\Leftrightarrow\left(4x+14+3x+9\right)\cdot\left(4x+14-3x-9\right)=0\)

\(\Leftrightarrow\left(7x+23\right)\left(x+5\right)=0\)

hay \(x\in\left\{-\dfrac{23}{7};-5\right\}\)

Answer 2

\(\Leftrightarrow\left(8x+14\right)^2=\left(9x+3\right)^2\)

\(\Leftrightarrow8x+14=9x+3\)

\(\Leftrightarrow x=11\)