Is 21,28,35 a right triangle?

I will mark the CORRECT answer Brainiest.

Solve the system by the elimination method. 2x + y - 4 = 0 2x - y - 4 = 0 when you eliminate y, what is the resulting equation? a.x = 0 b.4x = -8 c.4x = 8

Triangle abc is reflected over the line y=x triangle abc has points (-6,-,-1) and (-5,-6) what is the c coordinate

Write the equation for the parabola that has x− intercepts (−2,0) and (4,0) and y− intercept (0,4).