Evaluate Expressions (XEI301,401) Name Dec 5, Evaluating Expressions Example 1: Evaluate the expression for t = 12 t + 20 I DO (12) + 20 = 32 Example 2: Evaluate the expression for y = 4 4y + 2 4(4) = 18 ALWAYS SUBSTITUTE VALUE IN PARENTHESES
Evaluate Expressions (XEI301,401) Name Dec 5, Evaluating Expressions Example 3: Evaluate the expression for c = -5 c – 14 WE DO (-5) – 14 = -19 Example 4: Evaluate the expression for d = -8 3d + 5 3(-8) = -19
Evaluate Expressions (XEI301,401) Name Dec 5, Evaluating Expressions Example 5: Evaluate the expression for x = 3 I DO Example 6: Evaluate the expression for z = 3 4z 2 + 2z + 5 4(3) 2 + 2(3) + 5 4* SUBSTITUTE VALUE IN PARENTHESES Z 2 and Z are NOT LIKE TERMS = 47
Evaluate Expressions (XEI301,401) Name Dec 5, Evaluating Expressions Example 7: Evaluate the expression for x = -2 WE DO Example 8: Evaluate the expression for z = -4 5z – 2z (-4) + -2(-4) * * ALWAYS SUBSTITUTE VALUE IN PARENTHESES = -45 PLUS NEGATIVE!
Evaluate Expressions (XEI301,401) Name Dec 5, Evaluating Expressions with two or more variables Example 9: Evaluate the expression for x=2, y=3, z=5 3x + 5y – 3z WE DO 3(2) + 5(3) + -3(5) = 6 Different variables are NOT LIKE TERMS
Evaluate Expressions (XEI301,401) Name Dec 5, Evaluating Expressions with two or more variables Example 10: Evaluate the expression for x=2, y=3, z=5 3(x + y) + 7z WE DO 3(2) + 3(3) + 7(5) = 50 3x + 3y + 7z First, simplify by distributive property