Answer: Alex is 15 years
Step-by-step explanation:
Since Alex is w years old and her sister is three years younger than him. The age of his sister will be:
= w - 3.
We will then multiply their ages and equate to 180. This will be:
w × (w - 3) = 180
w² - 3w = 180
w² - 3w - 180 = 0
w² - 15w + 12w - 180 = 0
w(w - 15) + 12(w - 15) = 0
(w + 12)(w - 15)
w - 15 = 0
w = 0 + 15
w = 15 years
Alex is 15 years, her sister is 12 years.
