Share
Notifications

View all notifications
Advertisement

If 15(2x2 – Y2) = 7xy, Find X: Y; If X and Y Both Are Positive. - Mathematics

Login
Create free account


      Forgot password?

Question

If 15(2x2 – y2) = 7xy, find x: y; if x and y both are positive.

Solution

`15(2x^2 - y^2) = 7xy`

`(2x^2 - y^2)/(xy) = 7/15`

`(2x)/y - y/x = 7/15`

Let `x/y = a`

`∴ 2a - 1/a = 7/15`

`(2a^2 - 1)/a = 715`

`30a^2 - 15 = 7a`

`30a^2 - 7a - 15 = 0`

`30a^2 - 25a + 18a - 15 = 0`

5a(6a - 5) + 3(6a - 5) = 0

(6a - 5)(5a + 3) = 0

`a = 5/6, -3/5`

But a cannot be negative

∴ a = 5/6

`=> x/y = 5/6`

=> x : y = 5 : 6

  Is there an error in this question or solution?
Advertisement

APPEARS IN

 Selina Solution for Concise Mathematics for Class 10 ICSE (2020 (Latest))
Chapter 7: Ratio and Proportion (Including Properties and Uses)
Exercise 7(D) | Q: 8 | Page no. 102
Advertisement

Video TutorialsVIEW ALL [1]

If 15(2x2 – Y2) = 7xy, Find X: Y; If X and Y Both Are Positive. Concept: Ratios.
Advertisement
View in app×