If (3x + 7y - 3) (x + y – 15) is equivalent to (ax2 + by2 + 2hxy + 2gx + 2fy + c), then what will be the value of {hc + f – a}/gbh?
Show answer & explanation
Correct answer: D
Explanation
The correct answer is Option 4 i.e. -0.2
(3x + 7y - 3) (x + y – 15) = 3x2 + 7y2 + 10xy – 48x – 108y + 45
On comparing with (ax2 + by2 + 2hxy + 2gx + 2fy + c):
a = 3, b = 7, h = 5, g = -24, f = –54 and c = 45
Hence,
{hc + f – a}/gbh
= ((45 × 5) - 54 - 3)/(-24 × 7 × 5)
= 168/(-840) = -0.2