Question

Tìm x :

a) -(-7) - ( x + 4 ) = 6 - 2x

b) \(\frac{x+3}{2}=\frac{x+2}{3}\)

Answer 1

b) quy đồng bình thường

MSC:=6

\(\Leftrightarrow\frac{\left(x+3\right).3}{2.3}=\frac{\left(x+2\right).2}{3.2}\)

Mẫu = nhau=> tử bằng nhau: \(\left(x+3\right).3=\left(x+2\right).2\Leftrightarrow3x+9=2x+4\)(1)

Chuyển hết số hạng chứa "x" ẩn sang bên VT; hằng số để bên VP

\(\left(1\right)\Leftrightarrow3x-2x=4-9\)

\(\Leftrightarrow x=-5\) (hết!)

Answer 2

a, \(-\left(-7\right)-\left(x+4\right)=6-2x\)

\(\Leftrightarrow7-x-4=6-2x\Leftrightarrow-x+2x=6-7+4\)

\(\Leftrightarrow x\left(-1+2\right)=-1+4\Leftrightarrow x=3\)

Vậy x = 3

b, \(\frac{x+3}{2}=\frac{x+2}{3}\Rightarrow3\left(x+3\right)=2\left(x+2\right)\)

\(\Rightarrow3x+9=2x+4\Rightarrow3x-2x=4-9\)

\(\Rightarrow\left(3-2\right)x=-5\Rightarrow x=-5\)

Vậy x = -5

Answer 3

A) -(-7)-(x+4)=6-2x

7-x-4 =6 - 2x

7-4-x =6-2x

3-x =6-2x

-x+2x =6-3

x =3

b) \(\frac{x+3}{2}=\frac{x+2}{3}\)

\(\Rightarrow\left(x+3\right)\cdot3=\left(x+2\right)\cdot2\)

3x+3.3 = 2x + 2.2

3x + 9 = 2x + 4

3x-2x = 4-9

x = -5