RADIO TELESCOPES The cross-section of a large radio telescope is a parabola. The dish is set into the ground. The equation that describes the cross-section is d = x2 + 2x - 8 , where d gives the depth of the dish below
ground and x is the distance from the control center, both in meters. If the dish does not extend above the ground level,
what is the diameter of the dish? Solve by graphing.

check the picture below.

well, the angle at the vertex d is clearly not a right-angle, let's check for the one at the vertex f which does look like,   however if it's indeed, that means ef is perpendicular to df, in which case their slopes will be negative reciprocal of each other.

so the negative reciprocal of the slope of ef is 1, however the slope of df is not 1, is 1/2, so nope, they're not perpendicular lines.

it has the same slope and a different y-intercept

hope this : )

stop cheating

step-by-step explanation: