The problem asks to select all equations that are equivalent to $c - 18 = 15$. We need to use properties of equality to find which of the given equations have the same solution for $c$ as the original equation.

1. Problem Description

The problem asks to select all equations that are equivalent to $c - 18 = 15$. We need to use properties of equality to find which of the given equations have the same solution for $c$ as the original equation.

2. Solution Steps

First, we solve the given equation $c - 18 = 15$ for $c$.

Adding 18 to both sides of the equation, we get:

$c - 18 + 18 = 15 + 18$

$c = 33$

Now we check each of the other equations to see if they have the same solution $c = 33$.

Equation 1: $c - 16 = 15 + 2$

$c - 16 = 17$

Adding 16 to both sides, we get:

$c = 17 + 16$

$c = 33$

So, this equation is equivalent.

Equation 2: $c - 18 + 4 = 19$

$c - 14 = 19$

Adding 14 to both sides, we get:

$c = 19 + 14$

$c = 33$

So, this equation is equivalent.

Equation 3: $c - 3 = 15 + 15$

$c - 3 = 30$

Adding 3 to both sides, we get:

$c = 30 + 3$

$c = 33$

So, this equation is equivalent.

Equation 4: $c - 11 = 15 + 7$

$c - 11 = 22$

Adding 11 to both sides, we get:

$c = 22 + 11$

$c = 33$

So, this equation is equivalent.

3. Final Answer

All four equations are equivalent to the given equation.

c - 16 = 15 + 2

c - 18 + 4 = 19

c - 3 = 15 + 15

c - 11 = 15 + 7