Question

7 times a number is 18 less than the square of that number. Find the positive solution.

Answer 1

Step-by-step explanation:

Given  

7 times a number is 18 less than the square of that number. Find the positive solution.

Let the number be x

7 times a number will be 7x. So 7x is 18 less than the square of that number.

So 7x = x^2 – 18

Now x^2 – 7x – 18 = 0

So x^2 – 9x + 2x – 18 = 0

Now x(x – 9) + 2(x – 9) = 0

Or (x – 9)(x + 2) = 0

So we get x = 9, - 2

Therefore positive solution will be x = 9