Question

a^2+b^2=45, a+b=9,then a-b?

Answer 1

We know that:

(a+b)²+(a-b)²=a²+b²+2ab+a²+b²-2ab

==> 2a²+2b²

==>2(a²+b²)

So input the values:

9²+(a-b)²=45*2

==>(a-b)²=90-81

==>(a-b)²=9

==>a-b= + 3 or -3

The value is +3 or -3

Hope it helps

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Answer 2

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

9^2 =45+2ab

=>ab =18

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

=45-2(18)

=9

(a-b) =3