Question

Which is the value of 3b2-b when b=5?
a.20
b.25
c.70
d.75

Answer 1

3b2-b, we can re-write it as 6b-b

Now, substitute for b=5,

6(5)-5 = 30-5 =25

SO, OPTION B WOULD BE THE ANSWER.

Answer 2

Answer: The correct option is (c) 70.

Step-by-step explanation: We are given to find the value of the following expression for b = 5 :

`E=3b^2-b~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~(i)`

To find the value of the expression (i) at b = 5, we need to substitute b = 5 in (i).

Substituting b = 5 in (i), we get

`E\\\\=3b^2-b\\\\=3*5^2-5\\\\=75-5\\\\=70.`

Thus, the required value of the the given expression is 70.

Option (c) is CORRECT.