urgent help plzzzzzz

how do u do this

(edited 4 years ago)

I haven't done this kind of maths for a year or so so I may be wrong/confusing but:

1.find n by √16 then replace the ns in the formular with this number, and follow the formula to find the fraction, simplify this by the common denominator for the simplest form

2. I'm not entirely sure without writing it down I'm afraid, but for every 6x there's 5y
b. replace the X+ y with their values and solve each side of the ratio
X+3y=3
2x-y=1

sorry if this was of no help!!

Reply 2

OliviaLivOlivia

I can help with question 1: If n squared is 16, then n would be 4 because the square root of 16 is 4. Then just sub in 4 where n is. So, it would be 2x4 - 1 / 3x4 + 2, which is 7 / 14. Simplified would be 1/2 because both sides can be divided by 7.

Reply 3

Katie986

Question 1

Square root of 16 = 4 so n = 4.

((2 x 4) - 1) / ((3 x 4) + 2) = (8 - 1) / (12 + 2 ) = 7/14 = 1/2

Question 2
a) when you look at it, you can tell that x is some amount larger than y. Dividing by the smallest number in a ratio will always give you a ratio of 1 : something. So in this case, if you divide both numbers by 5, you get x : y = 1.2 : 1. The question asks x in terms of y, so what is x equal to? The new ratio tells us that x is 1.2 times bigger than y, so if you divide by 1.2, you get...

x = 1.2 y

b) this is a case of using what we did in part a to substitute into this new equation. We now know that x = 1.2 y, so let's substitute x for 1.2 y. You get...

1.2 y + 3 y : 2 (1.2 y) - y.

Now we'll simplify both sides.

4.2 y : 2.4 y - y

Simplify again.

4.2 y : 1.4 y

Dividing both sides by y removes that from the ratio.

4.2 : 1.4

Now the question tells us to prove that the actual ratio is 3:1. Our ratio is different but if we divide by the smallest number, that always gives us a ratio in the form of 1 : something. So we'll divide both sides by 1.4.

(4.2/1.4) : (1.4/1.4) = 3 : 1

Done :smile:

Reply 4

thara987

i think a few of you may be forgetting that the square root of 16 isn't just 4, it can be -4 as well. You could be penalised for not writing the -4 as well.

Reply 5

Katie986

Original post by thara987

i think a few of you may be forgetting that the square root of 16 isn't just 4, it can be -4 as well. You could be penalised for not writing the -4 as well.

Very true! Maybe this is why there's quite a few marks for that question.

Reply 6

thara987

Original post by Katie986

Very true! Maybe this is why there's quite a few marks for that question.

to be fair, i dont think it gets penalised at gcse (dont quote me on that, though), but the plus and minus answer gives me traumatic memories to when a question like this was given at an interveiw and i only answered in the positive and the interveiwers pointed it out. *shudder*

Reply 7

Katie986

Original post by thara987

It's been a while since I've done any proper maths, I'd completely forgotten that square root was a thing. During A levels I had memorised lots of square numbers but clearly didn't get to memorising the +/- part. It's funny how a bad experience makes something stick.