Grade 6 : Algebra - Expression - Example problem

1) Which expression represents 5 more than the product of 2 and  y ?

Solution

Product of 2 and y is  2*y or 2y

 5 more than the product of 2y is 2y + 5 or 5 + 2y

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2) Which value of b makes the inequality 3b > 12 true?

a) 2           b)3          c)4          d)5

Solution

Lets assume b=2

Replace b by 2 in 3b > 12

                          3*2 > 12

                           6 > 12 ( which is not true because 6 < 12)

Lets assume b=3

Replace b by 3 in 3b > 12

                          3*3 > 12

                           9 > 12 ( which is not true because 9 < 12)

Lets assume b=4

Replace b by 4 in 3b > 12

                          3*4 > 12

                           12 > 12 ( which is not true because 12 = 12)

Lets assume b=5

Replace b by 5 in 3b > 12

                          3*5 > 12

                           15 > 12 (yes, 15 is greater than 12 which is true)

Answer is d) 5