If $(40\sqrt{5}x^3 - 2\sqrt{2}y^3) ÷ (2\sqrt{5}x - \sqrt{2}y) = Ax^2 + By^2 - Cxy, $ then find the value of A + 3B - $\sqrt{10}C.$
Answer & explanation
Correct answer: option 2
If $(40\sqrt{5}x^3 - 2\sqrt{2}y^3) ÷ (2\sqrt{5}x - \sqrt{2}y) = Ax^2 + By^2 - Cxy, $ then find the value of A + 3B - $\sqrt{10}C.$
We know that,
a3 – b3 = (a – b)(a2 + b2 + ab)
(40√5x3 – 2√2y3) = [(2√5x – √2y)(2√5x)2 + (√2y)2 + 2√5 × √2]/(2√5x – √2y)
= (2√5x)2 + (√2y)2 + 2√5 × √2
= 20x2 + 2y2 + 2√10xy
Now,
Comparing all of them we get,
A = 20, B = 2 and C = -2√10
Now,
The value of A + 3B – √10C = (20 + 3 × 2 + 2√10 × √10)
= (20 + 6 + 20) = 46