The square of mark's age 3 years ago is 6 times the age he will be in 9 years. What is his age now?
An equation is a mathematical statement with an 'equal to' symbol between two algebraic expressions that have equal values.
Answer: Mark's current age is 15 years
We will solve a quadratic equation to find the answer to the given question.
Let Marks' current age be x years.
Marks' age 3 years ago = x - 3
Marks' age 9 years from now = x + 9
According to the question,
(x - 3)2 = 6 × (x + 9)
x2 + 9 - 6x = 6x + 54
x2 - 12x - 45 = 0
(x + 3) (x - 15) = 0
x = -3, 15