y is directly proportional to (d+2)^2, when d=5, y=147. d^2 is inversely proportional to x^2, when d=2, x=3. Find an equation for y in terms of x

Though this question initially appears complex, it can be broken down into logical steps that make the answer straightforward to find. The two statements should be approached individually, to give an equation for y in terms and d, and another for d in terms of x. The equation for d in terms of x can be substituted into the equation for y in terms of d, to give an equation for y in terms of x
Finding the first equationy ∝ (d+2)2y = k(d+2)2147 = k X 72147 = 49kk =3y = 3(d+2)2 (1)
Finding the second equationd2 ∝ 1/x2d2 = k/x24 = k/9k = 36d2 = 36/x2d = 6/x (2)
Subsituting for the final equationSubstituting (2) into (1)y = 3((6/x)+2)2

LR
Answered by Lucy R. Maths tutor

2553 Views

See similar Maths GCSE tutors

Related Maths GCSE answers

All answers ▸

Solve: 3x + 4 = x + 12


Emily bought 3 books and 2 apples, and she spent £19, while her brother, John, spent £15 on 1 book and 5 apples. What is the cost of one book and one apple?


What's the key to solving simultaneous equations?


Solve the following equation; 8x-2 > 4x +6


We're here to help

contact us iconContact ustelephone icon+44 (0) 203 773 6020
Facebook logoInstagram logoLinkedIn logo

MyTutor is part of the IXL family of brands:

© 2025 by IXL Learning