-10(5-7)=10.5-(-10.7)=-15-(-70)=-50 +70=20

The left side 20 is equal to the right side 20, which means that the given statement is always true.

True

answer:  

step-by-step explanation:

here x represents the height of the pole,

and, the height of the shadow of the pole is 12 feet.

also, the angle of elevation from the top of the pole is 40°,

therefore,

by the low of sine,

which is the required equation for finding the value of x,