Twice the difference of a number and seven is equal to four less than the product of five and the number. What is the value of n?

-10/3 = n

Step-by-step explanation:

let 'n' = number

2(n-7) = 5n-4

distribute the 2 to eliminate the parentheses:

2n - 14 = 5n - 4

subtract '2n' from each side to get:

-14 = 3n - 4

add 4 to each side to get:

-10 = 3n

-10/3 = n

the surface area is 124cm²

step-by-step explanation:

length: 4cm

width: 9cm

height:   2cm