y is proportional to x^2 and that when y = 75, x = 5. Find a formula for y in terms of x and find y when x=3
In a proportional equation, you represent the factor of proportionality as k. In this case it means that y=kx^2. In the question you're given a number for both y and x. Sub these in in order to solve for k. This would mean that 75=k(5)^2. This leads to 75=25k. This leads to k=3. The formula for y in terms of x is therefore y=3x^2.Now that you have k you can sub in the value given to you in the question for x in order to find y. This leads you to have y=3(3)^2. y=3(9)y=27.
KI
Related Maths GCSE answers
All answers ▸A ladder 6.2m long is leaning against a wall. The bottom of the ladder is 0.8m from the wall. Calculate the distance the ladder reaches up the wall, giving your answer to two decimal points.
How do you solve inequalities when you have two inequality symbols in the expression, e.g. 4x - 6 < 14 < 3x + 2
How do you solve simultaneous equations?
Bhavin, Max and Imran share 6000 rupees in the ratios 2 : 3 : 7 Imran then gives 3/5 of his share of the money to Bhavin. What percentage of the 6000 rupees does Bhavin now have? Give your answer correct to the nearest whole number.