C-3d = 11
-2c + 3d = -16

This looks like a system of equations:

We should solve for c on the first equation because we can substitute for c. There are a lot of ways we can do a system of equations, but I will do this.

c - 3d = 11

  +3d     +3d

c = 11 +3d

Now we can substitute.

-2(11+3d) + 3d = -16

solve

-22 + -6d + 3d = -16

-22 + -3d = -16

+22             +22

-3d = 6

/-3     /-3

d = -2

So we have found d. We can solve for c.

c - 3(-2) = 11

c + 6 = 11

  -6      -6

c = 5

Now we know both D and C. d=-2 and c=5

not only in mathematics, scientific proof also are required in the other field of science. also maths proofs are of particular structure, containing steps and logics. so proving is like doing science, it is science. that's why it is important to prove. 

an inaccurate proof leads to errors, or stating results that are not accurate.  which wil mess the probelm up you dont want this

what are the