Question

If the sum of a number and four is doubled, the result is one less than the number. Find the number.

Answer 1

Explanation:

Equation

2(x + 4) = x - 1

Solution

2x + 8 = x - 1 Subtract x from both sides

2x-x + 8 = - 1 Combine the left

x + 8 = - 1 Subtract 8 from both sides

x + 8-8 = - 1-8

x = - 9

Check

LHS

2(-9 + 4)

2(- 5)

-10

RHS

-9 - 1

- 10