Question

tìm x biết

A) (4x-1)²-(3x+2) (3x-2)=(7x-1) (x+2) + (2x+1)²-(4x¹+7)

B) (2x+3)²-(5x-4) (5x+4)=(x+5)²-(3x-1) (7x+2)-(x²-x+1)

C) (1-3x)²-(x-2) (9x+1)=(3x-4) (3x+4)-9(x+3)²

D) (3x+4) (3x-4) - (2x+5)²=(x-5)²+(2x+1)²-(x²-2x)+(x-1)² cần gắp

Answer 1

a) \(\left(4x-1\right)^2-\left(3x+2\right)\left(3x-2\right)=\left(7x-1\right)\left(x+2\right)+\left(2x+1\right)^2-\left(4x^2+7\right)\)(1)

\(\Leftrightarrow\left(16x^2-8x+1\right)-\left(9x^2-4\right)=\left(7x^2+14x-x-2\right)+\left(4x^2+4x+1\right)-\left(4x^2+7\right)\)

\(\Leftrightarrow16x^2-8x+1-9x^2+4=7x^2+13x-2+4x^2+4x+1-4x^2-7\)

\(\Leftrightarrow7x^2-8x+5=7x^2+17x-8\)

\(\Leftrightarrow7x^2-8x-7x^2-17x=-8-5\)

\(\Leftrightarrow-25x=-13\)

\(\Leftrightarrow x=\dfrac{13}{25}\)

Vậy tập nghiệm phương trình (1) là \(S=\left\{\dfrac{13}{25}\right\}\)

Answer 2

gắp cái gì