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.

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