so how do you find the intersection of $\displaystyle x^2+y^2=18$ and $\displaystyle y=x$ algebraically?
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Originally Posted by behindDkeys so how do you find the intersection of $\displaystyle x^2+y^2=18$ and $\displaystyle y=x$ algebraically? Substitute $\displaystyle y=x$ into $\displaystyle x^2+y^2=18$ Solve for x
Originally Posted by running-gag Substitute $\displaystyle y=x$ into $\displaystyle x^2+y^2=18$ Solve for x but then i'll get like positive and negative 9 do i substitute the value of x to each equation and right down what i got? then i'll get 4 solutions o.o is that right?
No It leads to x²=9 Then x=-3 or x=3 There are therefore 2 intersection points : (-3,-3) and (3,3)
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