Question

if x minus y is equal to 7 and x y is equal to 9 find the value of x square + y square​

Answer 1

Answer:

x-y=7

squaring both side

(x-y)²=7²

x²+y² - 2xy =49

x²+y² - 2 x 9 =49

x²+y² - 18= 49

x²+y² = 49 + 18

x²+y² = 67

Answer 2

Given,

${ \boxed{ \huge{ \text{x -- y = 7}}}} \\{ \boxed{ \huge{ \text{ \: \:xy = 9}}}}$

Therefore,

${ \boxed{ \mathbf{ \: \: \: \: \: \: \: \: \: \: \: \: \: {(x - y)}^{2} = {(7)}^{2}}}} \\ { \boxed{ \mathbf{ \: {x}^{2} + {y}^{2} - 2xy = 49}}} \\ { \boxed{ \mathbf{ {x}^{2} + {y}^{2} - 2(9) = 49 }}}\\ { \boxed{ \mathbf{ \: \: \: \: {x}^{2} + {y}^{2} - 18 = 49}}} \\{ \boxed{ \mathbf{ \: \: \: \: \: \: \: \: \: \: \: \: \: \: {x}^{2} + {y}^{2} = 49 + 18 }}}\\ { \boxed{ \mathbf{ \: \: \: \: \: \: \: \: \: \: \: \: \: \:{ \red{ {x}^{2} + {y}^{2} = 67}}}}}$