Substitution

What is substitution in algebra?

• The process of replacing a variable with a number or another expression to simplify or solve an equation.

• A method of factoring polynomials to find roots.

• A technique used to graph linear equations on a coordinate plane.

• A way to combine like terms in an algebraic expression.

If a = 4 and b = 6, what is the value of 3a + 5b?

• 30

• 36

• 42

• 48

How can you check your answer after evaluating an expression?

• By ignoring the substituted values and moving on

• By re-evaluating the expression with the substituted values to ensure the calculations are correct

• By asking someone else to check your work

• By writing down the answer and forgetting about it

What is the formula for calculating the value of an expression with two variables?

• The formula involves substituting the values of the two variables into the expression and simplifying it.

• The formula is to add the two variables together.

• The formula requires multiplying the two variables and then adding a constant.

• The formula is to divide the first variable by the second variable.

What is the value of 2c - a - b when a = 4, b = 5, and c = 6?

• 1

• 2

• 3

• 4

What is the result of 5m - 2n when m = 3 and n = 7?

• -1

• 0

• 1

• 2

What is the general approach to solving application-based questions in algebra?

• Understanding the problem, identifying the variables, substituting known values, and simplifying the expression to find the solution.

• Only substituting known values into the equation without understanding the problem.

• Ignoring the variables and focusing solely on the final answer.

• Using trial and error to guess the solution without any calculations.

How do you evaluate an expression like 7x - 1 when x = 5?

• 7(5) - 1 = 34

• 7(5) + 1 = 36

• 5(7) - 1 = 34

• 7(5) - 5 = 30

What is the importance of substitution in solving equations?

• It allows for the simplification of expressions and helps in finding the values of unknown variables.

• It is used to eliminate variables from equations entirely.

• It makes equations more complex and harder to solve.

• It is only useful in linear equations.

How do you find the value of an expression with three variables?

• Substitute the known values of the three variables into the expression and simplify to find the value.

• Multiply the three variables together to get the value.

• Add the three variables together and divide by three.

• Use the average of the three variables to estimate the value.