Answer:
Explanation:
x + y = 18
y = 18 - x
xy = 72
x(18 - x) = 72
-x² + 18x = 72
0 = 72 - 18x + x²
x = (18 ± √(18² - 4(1)(72))) / (2(1))
x = (18 ± 6)/2
x = 12
x = 6
3.4m questions
4.4m answers