You have equation:2c - d + 2 = 0

add d to both sides:2c + 2 = d

You have equation:3c + 2d + 10 = 0

substitute:3c + 2(2c + 2) + 10 = 0

multiply:3c + 4c + 4 + 10 = 0

add:7c + 14 = 0

subtract 14 from both sides:7c = -14

divide both sides by 7:c = -2

go back to equation:2c - d + 2 = 0

substitute:2(-2) - d + 2 = 0

multiply:-4 - d + 2 = 0

add:-2 - d = 0

add 2 to both sides:-d = 2

multiply by -1:d = -2

can you do the other one now?