EVALUATE FOR GIVEN VALUE OF VARIABLES

Evaluate the following expressions when

x = 8, y = 9 and z = 10

Problem 1 :

2∛-x - √y

Solution :

= 2∛-x - √y

Substitute x = 8 and y = 9

= 2∛-8 - √9

= 2(-2) - 3

= -4 - 3

= -7

Problem 2 :

z² + (xy/y) - 5

Solution :

= z² + xy/y - 5

Substitute x = 8, y = 9 and z = 10

= (10)² + (8) (9) / 9 - 5

= 100 + 72 / 4

= 172/4

= 43

Problem 3 :

-5|x - z| + 1/2 z

Solution :

= -5|x - z| + 1/2 z

Substitute x = 8 and z = 10

= -5|8 - 10| + 1/2 (10)

= -5|-2| + 5

= -5(2) + 5

= -10 + 5

= -5

Problem 4 :

What is -4 - 2x + 7 when x = -5?

a. -7          b. 1         c. 13          d. 21

Solution :

= -4 - 2x + 7

By applying x = -5 in equation

= -4 - 2(-5) + 7

= -4 + 10 + 7

= -4 + 17

= 13

So, option (c) is correct.

Problem 5 :

What is 4∛a - c√b + 6 when a = 27, b = 64 and c = -2?

a. 2            b. 22            c. 26           d. 34

Solution :

= 4∛a - c√b + 6

Substitute a = 27, b = 64 and c = -2

= 4∛27 - (-2)√64 + 6

= 4(3) + 2(8) + 6

= 12 + 16 + 6

= 34

So, option (d) is correct.

Problem 6 :

What is

|-5x + 6y| + √z / 5^x - 22

when x = 2, y = -13 and z = 81

Solution :

= |-5x + 6y| + √z / 5^x - 22

Substitute x = 2, y = -13 and z = 81

= |-5(2) + 6(-13)| + √81 / 5² - 22

= |-10 - 78| + 9 / 25 - 22

= |-88| + 9 / 3

= 88 + 9 / 3

= 97/3

= 32.3