Q9 of 59 Page 162

If 4x2 + y2 = 40 and xy = 6, find 2x + y.

4x2 + y2 = 40 …Equation (i)


xy = 6


⇒ 4xy = 24 …Equation (ii)


Adding Equation (i) and (ii)


4x2 + y2 + 2xy = 64


⇒ (2x + y)2 = 82


⇒ 2x + y = ±8


More from this chapter

All 59 →
7

If x + y = 7 and xy = 12, find x2 + y.

 8

If x + y = 12 and xy = 32, find x2 + y.

 10

If x – y = 3 and xy = 10, find x2 + y.

 11

If x + = 3, find x2 + and x3 +