Question

if x + y = 5 and xy = 3, what is the value of x^2 + y^2

Answer 1

Answer:

x+y=5

xy=3

so x=3/y

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

(x+y)^2=5^2

x^2+y^2+2xy=25

x^2+y^2+2*3=25

x^2+y^2=25-6

=19

Answer 2

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${\blue{\underline {\underline{ \mathtt{\pink{Step \: by \: Step \: Explanation:-}}}}}}$

It is given that,

x-y=5 -----(1)

xy = 24 ----(2)

______________________

we know the algebraic identity:

(x+y)² = (x-y)²+4xy

______________________

(x+y)²

= (x-y)²+4xy

= 5²+4×24

= 25+96

= 121

Now ,

x+y = ±√121

=> x+y = ±11