0.2 (d-b) = 0.3b+5-3+0.1d

0.2 (d-b) = 0.3b+5-3+0.1d

you first distribute the 0.2 to the d and b in the parentheses, you'll then get

0.2d-0.2b=0.3b+5-3+0.1d

now you make sure that the b variables are with each other on the same side of the equal sign. so you subtract 0.3b from both sides to get

0.2d-0.5b=5-3+0.1d

now do the same thing with the d variables so subtract 0.1d from both sides to get

0.1d-0.5b=5-3

now you can subtract 5-3 which is easy to get

0.1d-0.5b=2

now you have to figure out what d and b equal. so i'll do b first. all you do is use the equation you have now and pretend that d is 0 so substitute the 0 in with the d variable to get

0.1 (0) - 0.5b=2

now you divide - 0.5b from both sides to get

-0.5b/-0.5 = b 2/-0.5 = - 4

so now you know b = - 4

now you do sthe sane thing with b substitute with a 0 to get

0.1d-0.5 (0) = 2

then divide 0.1d from both sides to get

0.1d/0.1=b 2/0.1=20

now you know d = 20

(d=20, b=-4)