Question

if 3x + 5y = 16 ,xy=5 find 9x square + 25y square

Answer 1

Answer:

Step-by-step explanation:

given:

3x + 5y=11

xy=2

as a^2 + b^2 could be written as (a+b)^2 - 2ab

In the same manner,

9x^2 + 25y^2 could be written as

(3x+5y)^2 - 2(3x)(5y)

(3x + 5y)^2 - 30xy

now, substitute the given values.,

(11)^2 - 30 (2)

= 121 - 60

= 61.

so here,

9x^2 + 25y^2 = 61