Solve using linear combination

x-y=-7
x+y=7

a. (-7,0)
b. (7,0)
c. (0,7)
d. (0,-7)

Abird on top of a 200 ft bridge tower sees a man standing on the lower part of the bridge (which is 50 ft above the ground). the angle of depression from the bird is 26 ̊. how far is the man from the base of the bridge tower? with explanation and pictures .

If x-1 and x+3 are the factors of x3+10x2+ax+b find a and b

The angles in a triangle are represented by 5x, 8x, and 2x+9. what is the value of ? a.10.8 b.11.4 c.9.7 d.7.2