Question

Solve the equation 20 +7k = 8(k + 2).

Answer 1

k = 4

Explanation:

a) Simplify both sides of the equation.

20 + 7k = 8(k + 2)

20 + 7k = (8)(k) + (8)(2)

20 + 7k = 8k + 16

7k + 20 = 8k + 16

b) Subtract 8k from both sides.

7k + 20 − 8k = 8k + 16 − 8k

−k + 20 = 16

c) Subtract 20 from both sides.

−k + 20 − 20 = 16 − 20

−k = −4

Divide both sides by -1.

-k/-1 = -4/-1

k = 4

Answer 2

`k=4`.

Explanation:

1. Write the expression.

`20 +7k = 8(k + 2)`

2. Solve the parenthesis on the right hand side of the equation.

`20 +7k = 8k+16`

3. Subtract 20 from both sides of the equation.

`-20+20 +7k = 8k+16-20\\ \\7k = 8k-4`

4. Subtract 8k from both sides of the equation.

`7k-8k = 8k-4-8k\\ \\-k = -4`

5. Multiply both sides by "-1".

`(-1)-k = -4(-1)\\ \\k=4`

6. Verify.

`20 +7(4) = 8((4) + 2)\\ \\20 +28 = 8(6)\\ \\48=48`

7. Express the result.

`k=4`.