Question

Tìm x biết:

a)(x+3)^2+(x-2)(x+2)-2(x+1)=7

b)x(2x-1)-(x-2)(2x+3)=0

c)(x-1)(x+2)-x-2=0

d)x[(3x+2)+(x+1)^2-(2x-5)(2x+5)]=0

đ) 2x^2-7x+5=0

e) (2x+3)(x-5)=(2x+1)(2×+3)

Answer 1

chúc bạn học giỏi

Answer 2

a: \(\Leftrightarrow x^2+6x+9+x^2-4-2x-2=7\)

\(\Leftrightarrow2x^2+4x-4=0\)

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

\(\Leftrightarrow x^2+2x+1-3=0\)

\(\Leftrightarrow\left(x+1\right)^2=3\)

hay \(x\in\left\{-\sqrt{3}-1;\sqrt{3}-1\right\}\)

b: \(\Leftrightarrow2x^2-x-\left(2x^2+3x-4x-6\right)=0\)

\(\Leftrightarrow2x^2-x-2x^2+x+6=0\)

=>6=0(vô lý)

c: \(\Leftrightarrow\left(x+2\right)\left(x-1-1\right)=0\)

\(\Leftrightarrow\left(x+2\right)\left(x-2\right)=0\)

=>x=-2 hoặc x=2

đ: \(\Rightarrow2x^2-2x-5x+5=0\)

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

=>x=1 hoặc x=5/2