Question

if x+y=10 and xy=21 find x​

Answer 1

Answer:

y=7 or 3

x=3 or 7

Step-by-step explanation:

x+y=10. xy=21

x=10-y x=21/y

21/y+y=10

21+y²/y=10

21+y²=10y

y²-10y+21=0

y²-3y-7y+21=0

y(y-3)-7(y-3)=0

(y-7)(y-3)=0

y=7,3

when y=7, when y=3,

x=10-7 x=10-3

x=3. x=7.