y is directly proportional to (x-1)^2. When x=5, y=4. Find y when x=7.

The trick to finding y in this question is to interpret the clue in the question of 'directly proportional'. Directly proportional means that the y and the (x-1)2 scale by the same amount. Another way of saying this is that y is equal to (x-1)2 multiplied by some constant, say C, giving us: y = C*(x-1)2From here we can calculate C by inputting the information provided: y=4 when x=5.4 = C*(5-1)2 = C42 = C16Therefore C = 0.25Finally, we substitute x=7 to find the final answer:y = 0.25*(7-1)2 = 0.2562 = 0.2536 = 9

JS
Answered by Jonathan S. Maths tutor

10068 Views

See similar Maths GCSE tutors

Related Maths GCSE answers

All answers ▸

Solve the simultaneous equations. 2x + y =10 and x + y = 4


How can I factorise a quadratic equation?


Write down 9.02x10^-3 and 2.6x10^5?


Please explain how to multiply two exponential expressions


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