Question

If x+y=5 and xy=4, find x^2+y^2

Answer 1

Answer:

SOLUTION -

if x+y = 5 & xy = 4

now

(x+y)² = x²+2xy+y² (on squaring both sides)

(5)² = x² + 2×(4) + y² ( on putting the values of x+y & xy )

25 = x²+8+y²

x²+y² = 25–8

x²+y² = 17

now ,

(x-y)² = x² - 2xy + y²

(x-y)² = (x²+y²) - 2xy

on putting the values of x²+y² & xy

(x-y)² = 17 - 2(4)

(x-y)² = 17–8

(x-y)² = 9

(x-y) = √9

(x-y) = 3 ANSWER

Answer 2

Answer:

17

Step-by-step explanation:

x+y=5

then,x=5-y....(1)

Xy=4

y×(5-y)=4

5y-y^2=4

y^2-5y+4=0

y=1,4

if y=1,x=5-1=4

if y=4,x=5-4=1

x^2+y^2=1^2+4^2

x^2+y^2=1+16=17