Pleaseee cab someone help me out with this maths question
Y is directly proportional to the square of x.
When x=3, y=18. Calculate value of x when y=50
When x=3, y=18. Calculate value of x when y=50
Reply 1
5
Original post
by AbithegoatY is directly proportional to the square of x.
When x=3, y=18. Calculate value of x when y=50
When x=3, y=18. Calculate value of x when y=50
Y=kx^2
18=k(3)^2
k=2 (after dividing both sides by 9)
therefore Y=2x^2
50 = 2(x)^2
25 = x ^2 (divided by 2 and then take the square root of 25)
x = ±5
Reply 2
13
Hehe. Slow down buddy. I am normally good at these type of questions but the power (^2) is throwing me off. And why are there 2 values?
Reply 3
16
Original post
by R3NiY=kx^2
18=k(3)^2
k=2 (after dividing both sides by 9)
therefore Y=2x^2
50 = 2(x)^2
25 = x ^2 (divided by 2 and then take the square root of 25)
x = ±5
18=k(3)^2
k=2 (after dividing both sides by 9)
therefore Y=2x^2
50 = 2(x)^2
25 = x ^2 (divided by 2 and then take the square root of 25)
x = ±5
I'll let it go here, but please note that it is against forum rules to post full solutions - please stick to hints in future
Original post
by AbithegoatHehe. Slow down buddy. I am normally good at these type of questions but the power (^2) is throwing me off. And why are there 2 values?
Reply 4
5
Original post
by davrosI'll let it go here, but please note that it is against forum rules to post full solutions - please stick to hints in future
As per the above, you're told that y is proportional to the square of x, which means that you can write down y = kx^2. Are you happy with that as the starting point?
As per the above, you're told that y is proportional to the square of x, which means that you can write down y = kx^2. Are you happy with that as the starting point?
Hi there, my bad! I’m a new user, thanks for letting me know
Reply 5
13
Original post
by davrosI'll let it go here, but please note that it is against forum rules to post full solutions - please stick to hints in future
As per the above, you're told that y is proportional to the square of x, which means that you can write down y = kx^2. Are you happy with that as the starting point?
As per the above, you're told that y is proportional to the square of x, which means that you can write down y = kx^2. Are you happy with that as the starting point?
Says who davros? It's against the rules to help people... I am confused
Reply 6
13
Original post
by davrosI'll let it go here, but please note that it is against forum rules to post full solutions - please stick to hints in future
As per the above, you're told that y is proportional to the square of x, which means that you can write down y = kx^2. Are you happy with that as the starting point?
As per the above, you're told that y is proportional to the square of x, which means that you can write down y = kx^2. Are you happy with that as the starting point?
Ohhhhhh!!!!! I understand nowwww I wrote it as square root of x! Thanks guys.
Reply 7
16
Original post
by AbithegoatSays who davros? It's against the rules to help people... I am confused
It's not against the rules to "help" people, but it is against the rules to post full solutions. Here is a link to the posting guidelines for this forum:
**Posting Guidelines** - The Student Room
Most people can find solutions for themselves with a little nudge in the right direction or a few hints - as I think you've realised now with this question
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