**Yes, all questions of linear equations in two variables can be solved by the substitution method.**

The substitution method is a technique used to solve a system of linear equations by expressing one variable in terms of the other and substituting it into the other equation. This method is based on the principle that if two quantities are equal to the same quantity, they are equal to each other.

**Steps to solve linear equations using the substitution method:**

1. **Identify the two equations:** Begin by identifying the two linear equations that form the system.

2. **Choose one equation:** Select one of the equations and solve it for one variable in terms of the other. This step involves isolating one of the variables on one side of the equation.

3. **Substitute the expression:** Once one variable is isolated, substitute the expression obtained in the previous step into the other equation.

4. **Solve for the remaining variable:** Simplify the equation obtained after substitution and solve for the remaining variable.

5. **Find the value of the first variable:** Substitute the value of the second variable obtained in the previous step back into the expression obtained in step 2 to find the value of the first variable.

6. **Check the solution:** Verify the solution by substituting the values of both variables into both original equations. The solution should satisfy both equations.

**Example:**

Let's solve the system of equations using the substitution method:

Equation 1: 2x + y = 7
Equation 2: 3x - 2y = 4

1. Choose Equation 1: Solve it for y in terms of x.
2x + y = 7
y = 7 - 2x

2. Substitute the expression into Equation 2:
3x - 2(7 - 2x) = 4

3. Simplify and solve for x:
3x - 14 + 4x = 4
7x - 14 = 4
7x = 18
x = 18/7

4. Substitute the value of x back into Equation 1 to find y:
y = 7 - 2(18/7)
y = 7 - 36/7
y = 49/7 - 36/7
y = 13/7

5. Check the solution by substituting x = 18/7 and y = 13/7 into both original equations.

Hence, the solution to the system of linear equations is x = 18/7 and y = 13/7.