Question

twice the sum of a number and 7 is equal to 3

Answer 1

Let n = the number. 

Twice the sum of a number and 7 = 3 would be 2(n+7) = 3. Divide by 2 on both sides to get n+7 = 3/2. Then subtract 7 from both sides to isolate the variable n. 

n = 3/2 - 7. N = -5.5 or -11/2