Answer:


Step-by-step explanation:
Trapezoid ABCD is isosceles trapezoid, because AB = CD (given). In isosceles trapezoid, angles adjacent to the bases are congruent, then
Since BK ⊥ AD, the triangle ABK is right triangle. In this triangle, AB = 8, AK = 4. Note that the hypotenuse AB is twice the leg AK:
If in the right triangle the hypotenuse is twice the leg, then the angle opposite to this leg is 30°, so,

Since BK ⊥ AD, then BK ⊥ BC and

Thus,

Now,

The answer to 4+5/2•2-7 is -3
Answer:
<u>Set a system of equations:</u>

<u>Multiply the whole upper equation by 2 and the whole bottom equation by 1 so their x-value equals:</u>

<u>Subtract the upper equation by the bottom equation & solve for y:</u>

<u>Substitute in the y-value to a equation to find x:</u>

<u>Therefore, the answer would be:</u>
<u />