Question

Q, 9)
If 3x + 4y = 16 and xy= 4. Find the value of 9xsquare + 16ysquare
a. 160
b. 1600
С. 1726
d. 256​

Answer 1

Answer:

a. 160

Step-by-step explanation:

Given, xy=4

3x+4y=16

Squaring both sides,

(3x+4y)^2 = (16)^2

9x^2+16y^2+24xy = 256

9x^2+16y^2 =256 - 24xy

9x^2+16y^2= 256- 24(4) [As xy = 4]

9x^2+16y^2= 256- 96

= 160