Question

Three numbers are in the ratio 3:4:5. If the smallest is 2x−7, what is the product of the two other numbers?

Answer 1

The product is;

(80x^2-560x+ 980)/9

Explanation:

Here, we want to get the product of the two smaller numbers

let the mid number be y

3/4 = 2x-7/y

3y = 8x-28

y = (8x-28)/3

Let the biggest be z

3/5 = 2x-7/z

3z = 10x -35

z = (10x-35)/3

The product of the two other numbers is thus;

(10x-35)/3 * (8x-28)/3

= (10x-35)(8x-28)/9

(80x^2-280x - 280x + 980)9

= (80x^2 - 560x + 980)/9