Download Evaluating Expressions


To find the numerical value of the
expression, simply substitute the
variables in the expression with the
given number.
Evaluate: 2x + 7, if x = 4
Substitute 4 for x.
2(4) + 7
8 + 7 = 15
Evaluate: 3x + 2y – 9, if x = 4, y = 2
Substitute x and y
3(4) + 2(2) – 9
Follow the orders of operation.
12 + 4 – 9
16 – 9
7
Evaluate: 2x – 3xy + 4y, if x = 3, y = -5
Substitute in the numbers.
2(3) – 3(3)(-5) + 4(-5)
Use correct order of operations.
6 + 45 – 20
51 – 20
31
Evaluate: 2x2 + y2 – 5, if x=-5, y=7
Substitute for x and y
2
2(-5) + (7) – 5
-10 + 49 – 5
39 – 5
34!!!!
Incorrect
Correct
Evaluate x2, if x = -3
-32 = -9
Evaluate x2, if x = -3
(-3)2 = 9
Evaluate –x2, if x = -3
-(-3)2 = 32 =9
Evaluate –x2, if x = -3
-(-3)2 = -(9) = -9