Answer:
x+(x+30)=72
Step-by-step explanation:
if x is the smaller number and y is the bigger number, then according to the condition (one number is 30 more than the other) y=x+30.
It the sum of the two numbers is 72, then x+y=72.
After substitution y=x+30:
x+(x+30)=72; - the required equation.
⇔ 2x=42; ⇒ x=21 (it is the smaller number)
y=51 (it is the bigger number).
