Question

If a-b=4andab=45, then what is the value of a²-b²? Please guys tell this answer

Answer 1

Answer:

-74

Step-by-step explanation:

$(a-b)^{2} = a^{2} + b^{2} - 2ab$

$a^{2} + b^{2} =(a-b)^{2} +2ab$

$a^{2}+ b^{2} = 4^{2} +2*45$   (inputting values)

$a^{2} +b^{2} =16-90$

Answer 2

(a-b)^2 = a^2 - 2ab + b^2

or, 4^2 + 90 = a^2 + b^2

or, a^2 + b^2 = 106

Now, a^2 + b^2 = (a+b)^2 - 2ab

or, 106 + 90 = (a+b)^2

or, (a+b)^2 = 196

or, (a+b) = 14

So, a^2 - b^2 = (a+b) (a-b)

or, a^2 - b^2 = 14 × 4

or, a^2 - b^2 = 56