Substitution

Front

What is substitution in algebra?

Back

Substitution is a method used to solve systems of equations by replacing one variable with an expression that is equivalent to it.

Front

What is the first step in solving a system of equations by substitution?

Back

The first step is to solve one of the equations for one variable in terms of the other variable.

Front

If y = 2x + 3, what is the value of y when x = 4?

Back

y = 2(4) + 3 = 8 + 3 = 11.

Front

What does it mean to substitute a value into an equation?

Back

To substitute a value means to replace a variable in the equation with a specific number.

Front

How do you substitute in the equation 4x + 3y = 45 if y = 2x - 2?

Back

You replace y in the equation: 4x + 3(2x - 2) = 45.

Front

What is the result of substituting x = 5 into the expression 7x - 1?

Back

7(5) - 1 = 35 - 1 = 34.

Front

What is the second step in solving the system 4x - 8y = 4 after substituting y = -1x - 5?

Back

The second step is to simplify the equation: 4x + 8x + 40 = 4.

Front

What is the correct substitution for y in the equation 6x + 9y = 90 if y = x + 5?

Back

The correct substitution is 6x + 9(x + 5) = 90.

Front

If y = 4, what is the value of 3y + 5?

Back

3(4) + 5 = 12 + 5 = 17.

Front

What is the purpose of substitution in solving equations?

Back

The purpose is to simplify the equations to find the values of the variables.