Twice the difference of a number and 4 equals 7

Answer 1

2|x-4| = 7

is the algebraic version of "twice the difference of a number and seven equals four" The absolute value signs mean there are two possible interpretations, either

2(x-4)=7 or 2(4-x)=7

and two possible solutions for x

2x-8 =7

2x =15

x =15/2 = 7.5

or

8-2x = 7

2x =8-7 = 1

x = 1/2 = 0.5

You probably want 7 1/2 as the solution, but the problem is ambiguous

1/2 is another possible solution

Answer 2

Let x be the unknown number. Then we have the equation 2(x-4)=7 which implies that x=4+(7/2)=15/2.