Question

if x+y=3, x²+y²=5 then xy equals to​

Answer 1

Step-by-step explanation:

If x+y= 3, x²+y² = 5, then xy is what? xy = ? Substitute the value in the identity. Therefore, the value of xy is 2

Answer 2

Step-by-step explanation:

Find an expression for y

y = 3 - x

sub this into the second equation

x^2 + (3 - x)^2 = 5

then expand the brackets

x^2 + x^2 - 6x + 9 = 5

simplify

2(x^2 - 3x + 2) = 0

factorise

2(x - 2)(x - 1) = 0

so x = 2, 1

to find the y value sub into the original equation to get

y = 3 - 1 = 2

y = 3 - 2 = 1

so the solutions are

y = 2, x = 1

and

y = 1, x = 2