Question

When asked his age,Michael said if you square my age ,then subtract 12 times my age , the result is 85 how old is he

Answer 1

By the given statement,
${x}^{2} - 12x = 85$
${x}^{2} - 12x - 85 = 0$
Factorize if possible or use general solution for quadratic equation.
x2 - 17x + 5x - 85=0

x • (x-17)+ 5 • (x-17)=0

(x + 5) • (x - 17) = 0

Therefore,
(x + 5)=0 or (x - 17)=0
x=-5 or x=17
Discard the negative value
x=17 is considered.

Hence, Michael is 17yrs old