Question

Rút gọn biểu thức sau :

1, (3x+5)2+(3x-5)-(3x+2)(3x-2)

Answer 1

\(\left(3x+5\right)^2+\left(3x+5\right)-\left(3x+2\right)\left(3x-2\right)\)

\(=9x^2+30x+25+3x-5-\left[\left(3x\right)^2-2^2\right]\)

\(=9x^2+33x+20-9x^2+4\)

\(=33x+24\)

Answer 2

1.

\(2.\left(3x+5\right)+\left(3x-5\right)-\left(3x+2\right).\left(3x-2\right)\)

\(=6x+10+3x-5-\left(9x^2-4\right)\)

\(=9x+9+9x^2\)

\(=9.\left(x+x^2+1\right)\)