Question

If x + y = 7 and xy = 10, find the value of x
² + y².​

Answer 1

ANSWER:-

x² +y²=29

QUESTION:-

If x + y = 7 and xy = 10, find the value of x² +y²

TO FIND:-

x² +y²

GIIVEN:-

• x+y=7
• xy=10

EXPLANATION:-

IF x+y=7 then (x+y)² =7²

SO,

(x+y)² =7²  

x² +2xy+y² =49                { (x+y)² =x² +2xy+y²}

x² +2(10)+y²=49               {x+y=10 given}

x² +20+y²=49

x² +y²=49-20

x² +y²=29

Answer 2

$x + y = 7 \\ xy =1 0 \\ \: by \: applying \: \\ {(x + y)}^{2} = {x}^{2} + {y}^{2} + 2xy \\ substituting \: value \: we \: get \\ {7}^{2} = {x}^{2} + {y}^{2} + 2(10) \\ 49 = {x}^{2} + {y}^{2} + 20 \\ {x }^{2} + {y}^{2} = 49 - 20 \\ {x }^{2} + {y}^{2} = 29$