If 9x2+25y2=181 and xy=−6, find the value of 3x+5y.
9x2+25y2=181, and xy=−6(3x+5y)2=(3x)2+(5y)2+2×3x+5y⇒ 9x2+25y2+30xy=181+30×(−6)=181−180=1(3x+5y)2=(±1)2∴ 3x+5y=±1
If 9x2+25y2=181 and xy = - 6. Find the value of 3x + 5y.
Multiply 9x²+25y²+15xy+12x-20y+16 by 3x-5y-4 using suitable identity