Evaluating Algebraic expression and formula

Question 1

What do you mean Evaluate an expression

Answer 1

It means we need to find the numerical value

Question 2

How do we evaluate an expression such as

x + y

when x = 2 and y = 5

Answer 2

we replace the variable x with the number 2

and

we replace the variable y with the number 5

hence x + y = 2 + 5

= 7

Question 3

when x = 2 and y = 5

is xy = 25?

Answer 3

No, xy means x mulltiply by y

Hence xy = 2 * 5

= 10

Question 4

Find 2x + y

when x = 2 and y = 3

Answer 4

2(3) + 3 = 9

Question 5

Find 2x - y

when x = 2 and y = 3

Answer 5

2(3) - 3 = 3

Question 6

Find 2xy

when x = 2 and y = 3

Answer 6

2(2)(3) = 12

Question 7

Find 2x/y

when x = 2 and y = 3

Answer 7

2(2)/3 = 4/3

Question 8

Find 2x + y

when x = 2 and y = -3

Answer 8

2(3) + (-3) = 6 - 3

= 3

Question 9

Find 2x - y

when x = 2 and y = -3

Answer 9

2(3) - (-3) = 6 + 3

= 9

Question 10

Find 2xy

when x = 2 and y = -3

Answer 10

2(2)(-3) = -12

Question 11

Find 2x/y

when x = 2 and y = -3

Answer 11

2(2)/(-3) = -4/3

Question 12

What is a formula?

Answer 12

To find the area of a rectangle, we multiply the length and the breadth. This is an example of a formula

Question 13

Given that

Area = lb

find Area when l = 3 and b = 6

Answer 13

Area = 3 * 6

= 18

Question 14

Given that

Area = lb

find Area when l = 5 and b = 8

Answer 14

Area = 5 * 8

= 40