Solving x^2 + 2y = 9 w/ Sub Method

[wat2000]

use the subtitution method to solve.
x^2 + 2y = 9
x - y + 3 = 0


y=x+3 -> (3)
substitute for y with x+3, you get:
x^2+2(x+3)=9 x2+2x−3=0

factorize it to get:
(x+3)(x−1)=0 x=−3,x=1

substitute for each value of x in equation 3
x=−3y=−3+3=0

x=1y=1+3=4


(x,y)=(−3,0),(x,y)=(1,4)

Is this right?

 

[Mark44]

use the subtitution method to solve.
x^2 + 2y = 9
x - y + 3 = 0


y=x+3 -> (3)
substitute for y with x+3, you get:
x^2+2(x+3)=9 x2+2x−3=0

factorize it to get:
(x+3)(x−1)=0 x=−3,x=1

substitute for each value of x in equation 3
x=−3y=−3+3=0

x=1y=1+3=4


(x,y)=(−3,0),(x,y)=(1,4)

Is this right?

You can check for yourself. Do you get true statements for the two equations when x=-3, y = 0 and when x = 1, y = 4?

 

[js14]

So its right!