Question

The sum of the digits of a two-digit number is 8. if the number is multiplied by 4, the result is 104. write and solve a system of equations. find the number. solve using substitution.

Answer 1

Let
xy-------------> a two-digit number

we know that
xy=10x+y

x+y=8------> x=8-y-------> equation 1
(10x+y)*4=104----->divide by 4 both sides-----> 10x+y=26-----> equation 2

substitute equation 1 in equation 2
10*[8-y]+y=26------> 80-10y+y=26----> 9y=80-26----> y=54/9---> y=6
x=8-y-----> x=8-6----> x=2

the two-digit number is xy-----> 26

the answer is
26