SOLUTION: y=x^2−10 9x^2−y^2=90 solve the system by the substitution method

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Question 987137: y=x^2−10
9x^2−y^2=90
solve the system by the substitution method
Found 2 solutions by Alan3354, macston:
Answer by Alan3354(69443) About Me  (Show Source):
You can put this solution on YOUR website!
y=x^2 - 10
9x^2 - y^2=90
solve the system by the substitution method
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y=x^2 - 10 --> x^2 = y + 10
Sub for x^2 in the 2nd eqn.
9(y + 10) - y^2 = 90
9y - y^2 = 0
y = 0
y = 9
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Sub for y in any eqn to find x.

Answer by macston(5194) About Me  (Show Source):
You can put this solution on YOUR website!
.
y=x%5E2-10
y%2B10=x%5E2 Use this to substitute for x^2.
.
9x%5E2-y%5E2=90 Substitute for x^2.
9%28y%2B10%29-y%5E2=90
9y%2B90-y%5E2=90
9y-y%5E2=0
y%289-y%29=0
y=0 OR 9-y=0
y=0 OR 9=y
.
For y=0:
y=x%5E2-10
0=x%5E2-10
10=x%5E2
sqrt%2810%29=x
.
ANSWER 1: (%28plus_or_minus%29+sqrt%2810%29,0%29)
For other answers, substitute 9 the same way.