If 2a + 3b = 14 and 2a - 3b = 10, then find the value of 'ab'.
Show answer & explanation
Correct answer: C
Explanation
The correct answer is option 3 i.e. 4.
2a + 3b = 14......................1
2a - 3b = 10.....................2
Add equations 1 and 2
⇒ 4a = 24
⇒ a = 6
Now put the value of 'a' in equation 1
⇒ 12 + 3b = 14
⇒ b = 2/3
So, the value of ab = 6 × 2/3 = 4