Question

Me ajudem a resolver
X-y=5
X.y=84

Answer 1

Answer:

x-y = 5. -frist eq.

x. y = 84. -second eq.

from frist eq.

x-y = 5

x = 5+y

put the value of c

x in second eq.

x. y = 84

(5+y).y = 84

y²+5y -84 =0

y²+12y -7y -84 =0

y(y+12) -7(y+12)

(y+12) (y-7)

for zeros

y = -12

y = 7

Answer 2

Answer:

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

x.y=84------------(2)

-»x=84/y

put the value of x in eq (1)

84/y-y=5

84-y^2/y=5

84-y^2=5y

y^2+5y-84=0

y^2+12y-7y-84=0

y(y+12)-7(y+12)=0

(y+12)(y-7)=0

y+12=0. y-7=0

y=-12. y=7

when y is -12,

x=5+y=5+(-12)=5-12=-7

when y is 7,

x=5+y=5+7=12.