Question 842605
if karens age is x, and we know that karen is seans age + 5 lets form an equation.

let seans age be y such that y + 5 = x

if y * (y + 5) = 300 find the value of x

solve for y first

y^2 + 5y = 300

we now have a quadratic equation

y^2 + 5y - 300 = 0

You can solve it using any of the known methods: perhaps the easiest here would be the quadratic formula.

 {{{x = (-b +- sqrt( b^2-4*a*c ))/(2*a) }}}

a = 1; b = +5; c = -300

the result will be the roots -20 and 15; since age can't be less than 0 we can discard the first root.

so seans age is 15 and therefore karens age is 15+5 = 20 years