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

Answered by Jonathan S. Maths tutor

9445 Views

See similar Maths GCSE tutors

Related Maths GCSE answers

All answers ▸

A square, with sides of length x cm, is inside a circle. Each vertex of the square is on the circumference of the circle. The area of the circle is 49 cm^2. Work out the value of x. Give your answer correct to 3 significant figures.


Farmer Joe has a rectangular pen to hold his animals. The pen’s length is 5 meters longer than the width. The pen’s area is 84 meters. Find it’s width.


Solve x^2+6x+1=0 by completing the square


A box contains 7 caramel doughnuts. They have masses of 56 g, 67 g, 45 g, 56 g, 58 g, 49 g and 50 g. Find the median, mean and mode values of these masses. Bonus: What mass of doughnut could be added to the box to make the mean mass = 61 g.


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