Which equation represents a line which is parallel to the line y=-\frac{1}{2}x+8y=− 2 1 ​ x+8?

Answer 1

I am going to assume you meant (-1/2)x + 8y = -21x + 8

Clear fractions first, i.e. multiply the equation by 2

-x + 16y = -42x + 16

Collect terms

16y = -41x + 16

y= (-41/16)x + 1

Any equation of the form y = (-41/16)x + b will be parallel to the original line.