Question

Helppppp

Answer 1

\(2.\)

\(1.\left(x+2\right)\left(3x-4\right)+\left(x-3\right)^2=3x^2+2x-8+x^2-6x+9=4x^2-4x+1.\)

\(2.\left(2x-3\right)\left(2x+3\right)-4\left(x^2-2\right)=4x^2-9-4x^2+8=-1.\)

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

\(=x-2.\)

\(4.\left(3x-1\right)^2-\left(3x+1\right)\left(3x+4\right)=9x^2-6x+1-9x^2-15x-4\)

\(=-21x-3.\)

Answer 2

Bài 1: 

1: \(\Leftrightarrow x^2+2x+1-x^2+4x-4=4\)

=>6x-3=4

=>x=7/6

2: \(\Leftrightarrow x^2+4x+4+9-3x=3\)

\(\Leftrightarrow x^2+x+10=0\)

hay \(x\in\varnothing\)

3: \(\Leftrightarrow x^2-6x+9-x^2+16=0\)

=>-6x=-25

hay x=25/6

4: \(\Leftrightarrow4x^2-4x+1-2\left(2x^2-8x-x+4\right)=0\)

\(\Rightarrow4x^2-4x+1-4x^2+18x-8=0\)

=>14x-7=0

hay x=1/2