Question

If 9x^2+25y^2=181 and xy= -6, find the value of 3x+5y

Answer 1

Answer:

Mmmmm very tricky the answer is 2776

Answer 2

Solution

(3x+5y)²=9x²+25y²+2(3x)(5y)

=181+30xy

=181+30(-6)=1

(3x+5y)=√1=1