Question

If x + y = 8 and xy =15 , find 4x2 + y2.

Answer 1

Answer:

y=3 or

y=5

Step-by-step explanation:

x+y=8.......eq1

xy=15.....eq2

from 1

x=8-y.....eq3

eq3 in eq2

(8-y} x y=15

8y -y^2=15

y^2 - 8y +15=0

y^2-  5y - 3y +15=0

y{y-5}-3{y-5}=0

{y-3} {y-5}=0

y=3/5