What is 81-19+X-Y+21-X
If X=20 Y= -12

b. 153 students do not participate in sports and seventy-five 12th graders were surveyed

we have three similar triangles, because each has a right angle and shares an angle.   let's write the angles in order: opposite to short leg, long leg, hypotenuse.

cab similar to bad similar to cbd

or as ratios,

ca: ab: cb = ba: ad: bd = cb: bd: cd

we also know

ac = ad + cd

(ad+cd): ab: cb = ba: ad: bd = cb: bd: cd

(ad+cd)/cb=cb/cd

we have cb=6, ad=5 and seek x=cd.

we reject the negative root and conclude x=4

answer: 4

the answer is 13

step-by-step explanation:

5*5=25

12*12=144

25+144=169

169^2=13

faster, im not sure why but i know it is faster