Question

the larger of two numbers is five less than twice the smaller number. the sum of the two numbers is 16 find both numbers

Answer 1

A) L = (2 * S) -5
B) L + S = 16

A) (2*S) -5 -L =0
B) L + S =16
adding both equations
3S -5 = 15
3 S = 21

S=7
L = 16-S
L = 9

Answer 2

he/she was using algebra, where you substitute numbers for alphabets so you don't get confused when you solve equations

i mean, it would be a little silly to put it as
A) larger number = (2 * S) -5
B) larger number + smaller number = 16

A) (2*smaller number) -5 - larger number =0
B) larger number + smaller number =16
adding both equations
3(smaller number) -5 = 15
3(smaller number) = 21

and so on