The square of the hypotenuse of a right-angled triangle is equal to the sum of the squares of the other two sides.
You can use Pythagoras' Theorem to calculate QR:
a^2 + b^2 = c^2
5^2 + 12^2 = QR^2
25 + 144 = QR^2
169 = QR^2
This means that the square root of 169cm is QR, which is 13cm.
SR is equal to QR, which means that SR is 13cm.
As I understand from the given above, each box when empty weighs 5-2 kg or 3 kg. To determine the total weight of Michael's boxes when empty, we just have to multiply 3 kg by 5. This gives us an answer of 15 kg. Thus, the total mass of Michael's boxes is 15 kg.
Answer:

Step-by-step explanation:
In this question, you would solve for "a".
Solve:
K = 4a + 9ab
Since we have our "a" on the same side, we can factor it out from the variables:
K = a(9b + 4)
To get "a" by itself, we would have to divide both sides by 9b + 4:
K/9b+ 4 = a
Your answer would be K/9b+ 4 = a
It would look like this: 
Slope intercept form:
Y = mx + b
m = slope, b = y intercept
Given the slope of 4
Y = 4x + b
Plug in the point (3,8)
8 = 4(3) + b
8 = 12 + b, b = -4
Y intercept = -4
Solution: y = 4x - 4