
has CDF

where

is the CDF of

. Since

are iid. with the standard uniform distribution, we have

and so

Differentiate the CDF with respect to

to obtain the PDF:

i.e.

has a Beta distribution

.
Multiply first example by 3 and subtract by second example, you will get the following:
3*(5x + 2y) = 3*22 => 3*5x + 3*2y = 66 => 15x + 6y = 66
now subtraction:
(15x + 6y) - (-2x + 6y) = 66 - 3
15x + 6y + 2x - 6y = 63
15x + 2x + 6y - 6y = 63
17x = 63
x = 63/17 ≈ 3.705..... and as it says to round to the nearest tenth our answer would be: x = 3.7
The answer would be y = 6x.
The reason for this is that when we add a number in front of x, it makes it go up vertically by the factor of that number. So if we are to stretch the graph vertically, the only way we can do it is by making 6 the coefficient.