1+2+3+4+5+6+7+8+9+10+11+12+13+14+15 +16+17+18+19+20=
A)0
B)210
C)220
D)Brainliest

Solve 3x-18=2y and 5x-6y=14 by elimination or substitution . show all !

M∠abc=138° and m∠def=31° . which statement is true about ∠abc and ∠def ? a: the angles are neither complementary nor supplementary. b: the angles are complementary. c: the angles are supplementary.

The diameter of the moon is about 3500 km. approximate the surface area of the moon using the formula for the surface area of a sphere, s = 4πr2. write your answer in scientific notation.