Question

Tìm x, biết:

a) 2(x-5)-3(x+7)=14

b) 5(x-6)-2(x+3)=12

c) 3(x-4)-(8-x)=12

d) -7(3x-5)+2(7x-14)=28

=> THANKS TRƯỚC :))

Answer 1

a) 2(x - 5) - 3(x + 7) = 14

<=> 2x - 10 - 3x - 21 = 14

<=> 2x - 3x = 14 + 10 + 21

<=> x = -45

Vậy x = -45

b) 5(x - 6) - 2(x + 3) = 12

<=> 5x - 30 - 2x - 6 = 12

<=> 5x - 2x = 12 + 30 + 6

<=> 3x = 48

<=> x = 16

Vậy x = 16

c) 3(x - 4) - (8 - x) = 12

<=> 3x - 12 - 8 + x = 12

<=> 3x + x = 12 + 12 + 8

<=> 4x = 32

<=> x = 8

Vậy x = 8

d) -7(3x - 5) + (7x - 14) = 28

<=> -21x + 35 + 7x - 14 = 28

<=> -21x + 7x = 28 - 35 + 14

<=> -14x = 7

<=> x = -1/2

Vậy x = -1/2

Answer 2

\(a,2\left(x-5\right)-3\left(x+7\right)=14\)

\(\Leftrightarrow2x-10-3x-21=14\)

\(\Leftrightarrow-x=45\)

\(\Leftrightarrow x=-45\)

\(b,5\left(x-6\right)-2\left(x+3\right)=12\)

\(\Leftrightarrow5x-30-2x-6=12\)

\(\Leftrightarrow3x=48\)

\(\Leftrightarrow x=16\)

\(c,3\left(x-4\right)-\left(8-x\right)=12\)

\(\Leftrightarrow3x-12-8+x=12\)

\(\Leftrightarrow4x=32\)

\(\Leftrightarrow x=8\)

\(d,-7\left(3x-5\right)+2\left(7x-14\right)=28\)

\(\Leftrightarrow-21x+35+14x-28=28\)

\(\Leftrightarrow-7x=21\)

\(\Leftrightarrow x=-3\)