Question

solve all the questions I will mark you brainlist

Answer 1

10)( a+ 1/a)^2 = a^2 + 1/a^2 + 2

= 23 + 2

= 25

a + 1/a = +-5

11)( x -1/x)^2 = x^2 + 1/x^2 - 2

= 51 -2 = 49

x- 1/x = +-7



12)( 2.3)^2 - ( 0.3)^2)/ ( 2.3- 0.3)^2

= ( 2.3 + 0.3) ( 2.3 -0.3) / ( 2.3 - 0.3)^2

= ( 2.6) / ( 2)

= 13/10 = 1.3


13)3x - 4y = 10

xy = -1

( 3x -4y)^2 = 100

9x ^2 + 16 y^2 - 24 xy = 100

9 x^2 + 16 y^2 + 24 =100

9 x^2 + 16 y^2 = 76


14)5x - 2y = 7

xy = 2

(5x -2y)^2= 25x^2 + 4y^2 - 20 xy = 49

25 x^2 + 4y^2 - 40= 49

25 x^2 + 4y^2 = 89

( 5x +2y)^2 = 25 x^2 + 4y^2 + 20xy

= 89 + 40= 139


15) a + 1/a = 17/4

( a+ 1/a)^2 = ( 17/4)^2 = 289/16

a^2 + 1/a^2 + 2 = 289/16

a^2 + 1/a^2 = 289/16 - 2 = 289 - 32)/ 16

= 257/16

( a-1/a)^2 = a^2 + 1/a^2 -2

= 257/16 -2

= 257 - 32)/ 16 = 225/16

a- 1/a = 15/4

Answer 2

Hope this will help u... :-)