Help me answer this question please (use full working)

Step-by-step explanation:

The above variation is written as

y = kx²

where k is the constant of variation

when y = 20 and x = 1

we have

20 = k(1)²

k = 20

So the formula for the variation is

y = 20x²

when x is doubled that's x = 2

y = 20(2)²

y = 20(4)

when y = 80

We have

80 = 20x

Divide both sides by 20

Hope this helps you

=====================================

explanation

the graph has a slope of 1/3 because each time you move up 1, you go to the right 3. so, slope = rise/run = 1/3. we can cross choice a off the list since we want a slope of 3, rather than 1/3.

the first table shown has a slope of -3. this is because the rise is -6 and the run is 2, so slope = rise/run = -6/2 = -3. note how x increases by 2 each time (run) and y drops by 6 each time (rise). choice b can be eliminated.

the second table has a slope of 3. each time x goes up by 1, the y values increase by 3. slope = rise/run = 3/1 = 3. alternatively you can use the slope formula to prove that the slope is 3 here. use any two rows of values to generate the two points. choice c is one of the answers

the third table also has a slope of 3. let's use the slope formula to prove as such. i'm going to use the first two rows of the table. so i'll use the two points (2,1) and (5,10)

m = slope

m = (y2-y1)/(x2-x1)

m = (10-1)/(5-2)

m = 9/3

m = 3 so we get a slope of 3

choice d is the other answer

step-by-step explanation:

f