use cross products
(3r+6) *2 = 9*(2r-4)
6r+12 = 18r-36 distribute
12 = 12 r -36 subtract 6r from each side
48 = 12r add 36 to each side
4=r divide by 12
Answer: Maybe 5.7
Step-by-step explanation: To solve this we are going to need to understand the pythagorean theorem. we can use it as a way to find this certain side. if we put these numbers in the theorem, we get a^2+49=81 (7^2=49 and 9^2=81), we can subtract 49 on both sides and get 32. We would also need to take out the power of 2 on the side of the a^2, so you would do the square root of a^2, which would just become a and the square root of 32, which if you crunch the numbers on a calculator. You would get 5.656..... then you round it to the nearest tenth and get 5.7.
When 2 lines are parallel to each other mean than they have same gradient
y=5x +2
Gradient=5
Let the parallel equation be y=5x +c
Since this equation pass through (4,7), means that the point satisfy the parallel equation
7=5(4)+c
C=7-20=-13
So the parallel equation required is y=5x-13
Hope this can help.
3.1
the number of trucks reading horizontally from the vertical scale is
2 + 2 + 3 + 3 + 3 + 4 + 5 = 22
average number of trucks = 
= 3.1 ( to 1 dec. place)
