You can
put this solution on YOUR website!All you're doing is trying to isolate the variables from the numbers. So here it goes:

, <--add 3 to both sides so that you ONLY have 5d on one side
(5d-3)+3=(-18)+3

<--divide both sides by 5

=

d=-3

, <--subtract 3 from both sides
(3-4c)-3=-13-3

<--divide both sides by -4

=

c=4

, <--subtract 2x from both sides
(2x+1)-2x=(-4+7x-2x)

<--add 4 to both sides
(1)+4=(-4+5x)+4

<--divide both sides by 5

=

1=x
-4-5x=2x+10, <--add 5x to both sides

-4=7x+10 <--subtract 10 from both sides
(-4)-10=(7x+10)-10
-14=7x <--divide both sides by 7

=

-2=x
5r+2(r+1)=30,
5r+2r+2=30
7r+2=30
(7r+2)-2=(30)-2
7r=28

=

r=4
9m-4(m-3)=27
9m-4m+12=27
5m+12=27 <--subtract 12 from both sides
(5m+12)-12=(27)-12
5m=15 <--divide both sides by 5

=

m=3