15. A concrete slab is a cuboid. It measures 400 mm by 400 mm by 28 mm.
The density of the concrete is 2250 kg/mº.
Calculate the total mass of 60 slabs.

x² + 3x + 7 = 0       [ax² + bx + c]

a = 1

b = 3

c = 7

quadratic formula:

    (+/- is this ±)

plug in the numbers into the variables

your answer is a

1.) 21

2.) 0.453

3.) 1.5

4.) 48

5.) $ 22

step-by-step explanation: