Question

M.n júp mk vs ạ.

Tìm x biết

3.(x+5)-4.(x+7)=20.

Answer 1

3. (x+5) - 4.(x+7)=20

3x +15-4x-28 .    =20

                     -x .   =20+28-15

                      -x .  =33

                      x.    -33

Answer 2

3(x+5)-4(x+7)=20

<=> 3x+15-4x-28=20

<=> -x-13=20

<=> x+13=-20

<=> x=-33

Answer 3

Ta có: \(3.\left(x+5\right)-4.\left(x+7\right)=20\)

\(\Rightarrow3.x+15-4.x-28=20\)

\(\Rightarrow-x=20+28-15\)

\(\Rightarrow-x=33\)

\(\Rightarrow x=-\left(33\right)\)

Answer 4

3.(x+5) - 4.(x+7) = 20

\(\Leftrightarrow\)3x + 15 - 4x - 28 = 20

\(\Leftrightarrow\)-x - 13 = 20

\(\Leftrightarrow\)x + 13 = -20

\(\Leftrightarrow\)x = -33