It does represent a direct variation.
Direct variation: y = kx
y varies directly with x
Your equation 2y = 5x + 1 is in the form of y = kx but we need to divide out the 2 from 2y so we have the following
2y = 5x + 1
2y / 2 = 5 x/ 2 + 1/2
y = 5x / 2 + 1/2
y = kx
k = 5/2
k = constant of variation = 5/2
Answer: -42
Step-by-step explanation: 2*2 matrices are easy to find the determinant with. Its just ad-bc, so (5*-2)-(4*8), which is -42
A meter is 100 cm. So, the final length is

cm.
150 cm.
The slope of the line is m, variable m is the slope