Question

3x+4y=16 and xy=4
Find values of 9x^2+16y^2

Answer 1

Answer:

9x^2+16y^2=140

Step-by-step explanation:

3x+4y=16. xy=4

(3x+4y)^2=(16)^2. Opening brackets

(3x)^2+(4y)^2+2(3x)(4y)=256 [using property (a+b)^2=a^2+b^2+2ab]

9x^2+16y^2+24xy=256 [putting the value of xy given in the question]

9x^2+16y^2+(24*4)=256

9x^2+16y^2+96=256 [Using Transposing method]

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

9x^2+16y^2=140