Presentation on theme: "ALGEBRA LESSON 2 EVALUATING EXPRESSIONS AND CHECKING."— Presentation transcript:
ALGEBRA LESSON 2 EVALUATING EXPRESSIONS AND CHECKING
Evaluating Expressions Given an algebraic expression, you will plug given numbers in for the variables and perform the operations. Example: Find the value of x + 3 if x = 7 In this case, you will replace the x with 7 7 + 3 = 10 REMEMBER TO FOLLOW ORDER OF OPERATIONS FOR THOSE PROBLEMS WITH MORE THAN ONE OPERATION.
MORE EXAMPLES Evaluate the following if a = 7 3a a + 9 12 – a 3a + 4
MORE EXAMPLES Evaluate the following if x = 3 4x 2x – 5 9 – 2x 5x + 2 Evaluate the following if y = -5 y – 7 9 – y 3y + 6 35 – 6y
MORE EXAMPLES Evaluate the following if a = 2 and b = -3 3a + b 3b + a 2b – 2a 5ab Evaluate the following if x = 9, y = -2, and z = 3 xyz 2x – z -2y – z x – 3y
CHECKING ANSWERS FOR ALGEBRAIC EQUATIONS When we start solving equations (tomorrow), you can use what we learned today to CHECK to see if your answer is correct. Simply plug the answer you received into the equation that you started with to see if you get the same result of the original problem Ex. 3x = 27you get an answer of 9 Check this by plugging 9 in for x….do you get 27?