Question

In a farm, there are 600 banana trees. The number of tress in each row is 10 less than twice the number of rows. How many trees are in each rows?

Answer 1

let x = number of rows

that means 600/x = number of trees per row

it says the number of trees per row is also 10 less than twice the number of rows so

600/x = 2x - 10

make sense?

now multiply all terms by x

600 = 2x^2 - 10x

turn it into general form of quadratic equation

2x^2 - 10x - 600 = 0

divide everything by 2 (to make it simpler)

x^2 - 5x - 300 = 0

factor it out

(x-20)(x+15) = 0

solve for x

x = 20; x = -15

obviously it's impossible to be negative so take the positive root

does that help?