What is the result of subtracting the second equation from the first? -2x+y=0 and -7x+3y=2

In triangle △abc, ∠abc=90°, bh is an altitude. find the missing lengths. ac=26 and ch=8, find bh.

The construction of copying qpr is started below. the next step is to set the width of the compass to the length of ab. how does this step ensure that a new angle will be congruent to the original angle? by using compass take the measures of angle and draw the same arc according to it.

The measure of angle theta is 3 pi over 2. the measure of its reference angle is pi /