Question

One positive number is 7 more than twice another. If their product is 1425, find the numbers.

Answer 1

Answer:

25 and 57.

Step-by-step explanation:

Let the lowest number be x then the other is 2x + 7, So:

x(2x + 7) = 1425

2x^2 + 7x - 1425 = 0

2 * - 1425 = -2850 = -2 * 3 * 5 * 5 * 19

We need 2 numbers whose product is -2850 and whose sum is + 7.

These are 3 * 19 = 57 and -2* 5 * 5 = -50 so we write:

2x^2 - 50x + 57x - 1425 = 0  Now we factor by grouping:

2x(x - 25) + 57( x - 25) = 0)

(2x + 57) ( x - 25) = 0

x = -57, 25.

We ignore the negative as we are given that the number is positive,

x = 25 is one number and the other is 2(25) + 7 = 57.