2c-d=-2 4c+d=20?

Answer 1

4(2c-d=-2)
4(4c+d=20)
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8c-4d=-8
16c+4d=80
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24c=72
c=3
4(3)+d=20
12+d=20
d=8
(3,8)

2(3)-8=-2
6-8=-2
-2=-2

4(3)+8=20
12+8=20
20=20

Answer 2

(1) 2c-d=-2
(2) 4c+d=20

rearrange (2) to d=20-4c; then sub into (1) to get 2c-(20-4c)=-2, call this equation (3)

expand (3) to get 2c-20+4c=-2; simplify to get 6c=18. Therefore c=3

sub c=3 into (1) to get 2(3)-d=-2 & simplify to get 6-d=-2
therefore d=8

check (2) by using c=3 & d=8: 4(3)+8=20; 12+8=20

Answer 3

2c-d=-2 equation(1)
4c+d=20 equation(2)
by adding the two equations
6c=18
c=3
d=8

Answer 4

I know how to do this, but it is kind of hard to explain. c= -9 and d= 56. I am guessing that is right. For the 4c+d=20 you just subtract 4c from both sides. So you would get d=20-4c. then you just plug that into the first equation to get c. then when you get c you plug it into 20-4c.

Answer 5

2c - d = 24c + d = 20

2c - d - 2c = 24c + d = 2c = 20

- d = 22c + d = 20

- d + d = 22c + d + d = 20

0 = 22c + 2d = 20

22c + 2d = 20

2(11c + d) = 20

- - - - - -s-

Answer 6

adding
6c=18
dividing by 6
c=3
substituting in 2c-d=-2
2(3)-d=-2
ading -6
-d=-8
so d=8
solution set{3,8}