Which value of x would make tv=qs ?

Select the correct answer from the drop-down menu. subtracting 3xy^2 from 8xy^2 gives the same result as the expression. [tex]3xy ^{2} - 8xy ^{2} [/tex][tex] { - 7xy}^{2} - {2xy}^{2} [/tex][tex] {7xy}^{2} - {2xy}^{2} [/tex]

Which is the equation of a line perpendicular to the line with the equation 3x+4y=8

[10 points, algebra 2]according to my answer key the restrictions are -1 and 4. but why not positive 1?