Question

tìm x biết

1/ (x+1)(-3)+5(x-4)=-3

2/ 3(5x-1) -x (x+1)+x^2=14

3/ 2(x-1)-x(3-x)=x^2

4/ 3x(x+5)-2(x+5)=3x^2

5/ 4x(x+2)+x(4-x)=3x^2+12

Answer 1

1/ (x+1)(-3)+5(x-4)=-3

\(\Leftrightarrow\)-3x - 3 + 5x - 20= -3

\(\Leftrightarrow\)2x - 23=-3

\(\Leftrightarrow\)x=10

2/3(5x-1) -x (x+1)+x²=14

\(\Leftrightarrow\)15x - 3 - x² -x + x²=14

\(\Leftrightarrow\)14x=17

\(\Leftrightarrow\)x=17/14

3/2(x-1)-x(3-x)=x²

\(\Leftrightarrow\)2x - 2 - 3x + x²=x²

\(\Leftrightarrow\)2x-3x+x²-x²=2

\(\Leftrightarrow\)x= -2

4/ 3x(x+5)-2(x+5)=3x²

\(\Leftrightarrow\)3x² + 15x - 2x - 10=3x²

\(\Leftrightarrow\)13x = 10

\(\Leftrightarrow\)x=10/13

5/ 4x(x+2)+x(4-x)=3x²+12

\(\Leftrightarrow\)4x² + 8x + 4x - x² = 3x² + 12

\(\Leftrightarrow\)12x=12

\(\Leftrightarrow\)x=1