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GCSE MATHS PLEASE HELP

GCSE MATHS PLEASE HELP-example-1
User BradleyIW
by
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2 Answers

5 votes

Answer:

see explanation

Explanation:

(a)

given y varies inversely as x² then the equation relating them is

y =
(k)/(x^2) ← k is the constant of variation

to find k substitute any ordered pair from the table into the equation

using (2, 4 ) , then

4 =
(k)/(2^2) =
(k)/(4) ( multiply both sides by 4 )

16 = k

y =
(16)/(x^2) ← equation of variation

(b)

when y = 25 , then

25 =
(16)/(x^2) ( multiply both sides by x² )

25x² = 16 ( divide both sides by 25 )

x² =
(16)/(25) ( take the square root of both sides )

x = ±
\sqrt{(16)/(25) } = ±
(4)/(5)

the positive value of x is x =
(4)/(5)

User Gerwald
by
5.5k points
3 votes

Answer:

A) y = 16/(x^2), B) 4/5

Explanation:

For A, we can plug in some of the table values to check it. I will try 2 and 3

2. 4 = 16 / (2^2)

16/4 = 4

3. 16/9 = 16 / (3^2)

16/9 = 16/9

B) We can just input y into the formula 25 = 16 / (x^2)

This leaves us with +-4/5

User Praveen G
by
5.3k points