Good morning ☕️
Answer:
37
Step-by-step explanation:
Let our number be “ xy ”
the tens digit is four less than the units digit means y-4=x
Seven times the tens digit plus five times the units digit is equal to 56 means
7x+5y=56
now we have to solve the system:
y-4=x (1)
7x+5y=56 (2)
(1) ⇒ y=4+x
Then we substitute y by 4+x into the second equation like this:
7x+5(x+4)=56
⇔ 7x+5(x+4)=56
⇔ 12x+20=56
⇔ x = 3
now using equation (1) we get : y=3+4 = 7
:)
