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

2268 Views

See similar Maths GCSE tutors

Related Maths GCSE answers

All answers ▸

The probability of pulling out a coloured counter from a bag is shown below: Green=0.2. Purple=0.15. Black=0.3. Pink=?. What is the probability of pulling out a pink counter?


solve: x^2= 4(x-3)^2


Solve the simultaneous equations: y=x^2+4x-2, y=x+2


If f(x) = 2x+5, g(x) = 8x-7 and f(x)=g(x). Find the value of x. Show your working.


We're here to help

contact us iconContact usWhatsapp logoMessage us on Whatsapptelephone icon+44 (0) 203 773 6020
Facebook logoInstagram logoLinkedIn logo

© MyTutorWeb Ltd 2013–2025

Terms & Conditions|Privacy Policy
Cookie Preferences