Question

find the value of the following expressions if a=4 and b=2 (I). 3ab​-4b+5​

Answer 1

Answer: 21

We can substitute the values of a and b in the expression so that we can get to the answer. So here,

 3ab ​- 4b + 5​

= 3 (4) (2) - 4 (2) + 5

= 3 × 4 × 2 - 4 × 2 + 5

= 12 × 2 - 8 + 5

= 24 - 8 + 5

= 24 - 3

= 21

So the value for the expression 3ab ​- 4b + 5​ is 21.

Additional Information

When a number is right next to another number which is brackets, it means you have to multiply them, for example if it is written that 3 (4) then that means you have to multiply 3 by 4 to get 12.

Answer 2

Given,

$3ab-4b+5$

If $a=4$ and $b=2$

We have to find the value of given expression

Substitute given values in the given expression

$3ab-4b+5=3\times4\times2-4\times2+5$

$= 24-8+5\\=16+5\\=21$

Therefore, the value of given expression is $21$.