Ans 3: (Master Answer)
The place value and face value of a digit in a number is always equal at one's place.
Checkout this video to understad the concept better.
In a school, 8a2 + 4a + 9 students were enrolled. 2a2 – 9a + 2 students were boys. How many girls were enrolled?
A 6a2 – 13a + 7
B 4a2 + 13a + 7
C 6a2 + 13a + 7
D 4a2 – 13a + 7
Answer is C because number students enrolled -number of boys enrolled=number of girls enrolled