Exercise 18 Page 85

To solve the equation we need to isolate c on one side of the equation. By subtracting 4 from both sides, we can cancel it from the left-hand side.

c+4=-9

SubEqn

LHS-4=RHS-4

c+4-4=-9-4

SubTerm

Subtract term

c=-13

Therefore, c=-13 is the solution to the equation. To check that we have the correct solution, we can substitute c=-13 into the original equation and simplify.

c+4=-9

Substitute

c= -13

-13+4? =-9

AddTerms

Add terms

-9=-9

Since the left-hand side and right-hand side are equal, c=-13 is the correct solution.