Word problem: Finding a number from hints

Three times the result of subtracting a certain number from 7 gives the same answer as adding eleven to the number. Translate the problem into an equation and find the number.

3(7-x) = x+11
21-3x = x+11
4x = 10
x = 5/2

Turn each set of words into a term in the equation. Call the number n:

7 - n [subtracting a certain number from 7]

3(7 - n) [Three times the result]

= [gives the same answer]

n + 11 [adding eleven to the number]

The equation is:

3(7 - n) = n + 11

Multiply out the left side:

21 - 3n = n + 11

Add 3n to both sides:

21 = 4n + 11

Subtract 11 from both sides and flip it around:

4n = 10

Divide both sides by 4:

n = 10/4 which reduces to 5/2 (or 2 1/2 as a mixed number]

Check:

3[7 - (5/2)] ?= (5/2) + 11

3 * (9/2) ?= 27/2

27/2 = 27/2 [answer is correct]

3(x - 7) = x + 11
3x - 21 = x + 11
3x - x = 11 + 21
2x = 32
x = 16 answer//

3*(7-x) = x+11
21 - 3x = x + 11
21 - 11 = x + 3x
10 = 4x
x = 2½

Checking: 13½ = 13½

3(7-x)=x+11
21-3x=x+11
4x=10
x=5/2

~David

3(7-x)=x+11
-3x+21=x+11
10=4x
x=5/2