Question

13 ) If a + b = 9 and ab = -22, find a^2 - b^2​

Answer 1

Step-by-step explanation:

a−b=0.9

Squaring both sides,

=>(a−b)

2

=(0.9)

2

=>a

2

+b

2

−2ab=0.81

=>a

2

+b

2

=0.81+2(0.36)

=>a

2

+b

2

=1.53

Again,

(a+b)

2

=a

2

+b

2

+2ab

=1.53+2(.036)

=1.53+0.72

=2.25

=>a+b=

2.25

=±1.5

Now,

(a

2

−b

2

)=(a+b)(a−b)

=±(1.5)(0.9)

=±1.35