Solve y=2x-12 and y=-2x-4 using substitution

Which math sentence can be used to determine if the triangle is a right triangle?

Find the volume of the described solid.the solid lies between planes perpendicular to the x-axis at x = 0 and x=7. the cross sectionsperpendicular to the x-axis between these planes are squares whose bases run from the parabolay=-31x to the parabola y = 30/x.a) 441b) 147c) 864d) 882

0if x and y vary inversely and y=6 as x=7, what is the constant of variation?