Question

7. If x - = 5, then the value x2
+
1S​

Answer 1

ANSWER

Given x=

x−5

1

x(x−5)=1

x

2

−5x=1

divide by x, we get

x−5=

x

1

x−

x

1

=5 ....(1)

Squaring both ride

(x−

x

1

)

2

=25

x

2

+

x

2

1

−2=25

Adding 4 both rides.

x

2

+

x

2

1

+2=29

(x+

x

1

)

2

=29

(x+

x

1

)=

29

....(ii)

Multiply (1) and (2) we have

x

2

−

x

2

1

=5

29