Question

Giải pt:
3 - 4x(25 - 2x) = 8x² + x - 300

Answer 1

3 − 4x(25 − 2x) = 8x² + x − 300

3 − 100x + 8x² = 8x² + x − 300
−100x + 8x² − 8x² − x = −300 − 3
−101x = −303
x = −303 : (−101)

x = 3

Vậy S = {3}

Answer 2

\(\text{3 - 4x(25 - 2x) = 8x^2 + x - 300 }\)

\(\Leftrightarrow3-100x+8x^2=8x^2+x-300\)

\(\Leftrightarrow3-100x+8x^2-8x^2-x+300=0\)

\(\Leftrightarrow-101x+303=0\)

\(\Leftrightarrow-101\left(x-3\right)=0\)

\(\Leftrightarrow\)\(\left[{}\begin{matrix}-101=0\left(loại\right)\\x-3=0\end{matrix}\right.\)

\(\Leftrightarrow x=3\)

Mình không chắc đúng nhá