Question

c)√x+Y=7 -X+Y=-5 me ajudem pfvr ​

Answer 1

C)

√x+Y=7

-X+Y=-5



" y =7 - √x"

y = - 5+x"

"-5+x =7-√x"

"-5-7+x= (-√x)"

(-12+x) = (-√x)²

(x - 12)²= x"

" x² - 2.12.x + 144= x"

"x²-24x-x+144= 0"

"x²-25x+144= 0"

"a = 1; b = -25; c =144"

∆= (-25)²- 4.1.144

∆= 625-576"

∆= "49"

"x =[-b+/- √∆]/2.a"

x= [-(- 25)+/- √49]/2.1"

" x = [25+/-7]/2"

x' = (25+7)/2= 32/2= "16"

x " = (25-7)/2= 18/2= "9"

"Para x =9"

y= -5+x"

y= -5+9

"y = 4"

para x = 16

"y = - 5+x"

"y= -5+16

y = "11" não serve

√x+Y=7

=√16+11=4+11="15" (diferente de 7)"

-X+Y=-5

R.: "X =9; y = 4"

√x+Y=7

√9+4=3+4=7(ok)

-X+Y=-5

"-9+4 = -5" (ok)