Question

if x+y=12 and xy =14, find the value of x²+y² ​

Answer 1

${x}^{2} + {y}^{2} \: = \: {(x + y)}^{2} - 2xy$

${x}^{2} + {y}^{2} \: = \: {12}^{2} - 2(14)$

${x}^{2} + {y}^{2} \: = \:144 - 28$

${x}^{2} + {y}^{2} \: = \:116$

Answer 2

x + y = 12

Squaring both sides ,

(x+y)²= 12^2

x²+y²+ 2xy = 144

x²+y²+ 2(14) = 144

x²+y² = 144- 28

x²+y² = 116