Help
let's start with 7 - what are the shapes of the two graphs given?
line and ellipse
well the first equation is an ellipse
good, so that's it for part I for part II since y = x + 1 we can plug this into equation 1 to get x^2 + 4(x+1)^2 = 4 solve for your two x values
0,-8/5
good since y = x + 1 the y-coordinates are just the x-coordinates + 1 (going to do the arithmetic to save some time) (0,1) and (-8/5,-3/5) as your solutions
anyway, that's part II (just the xvalues) and part III (the x,y, coordinates)
for part 8 I) what shapes are these?
circle and hyperbola
good for part II simply solve y^2 - x^2 - 9 = 0 for x^2 (not x, solve for x^2)
6?
take this equation y^2 - x^2 - 9 = 0 add x^2 to both sides, what do you get?
y^2+2x^2-9=0+x^2
-x^2 + x^2 = ?
0
good so y^2 - x^2 + x^2 - 9 = x^2 x^2 = y^2 - 9 which is your sol'n for part II
then for part III plug this value of x^2 into the x^2 from equation 1 (y^2-9) +y^2 - 16y + 39 solve for y, should get two numbers
just need to combine like terms 2y^2 - 16y + 30 then factor this
the equation should be equal to 0
3 5
awesome, so those are your y-values for part III then for part IV plug these back into equation 2 to figure out what the x values would be
5^2-3^2-9=0
3 and 5 are your y-values not your x values remember when you are solving for an equation there should be one unknown variable, it can't all be numbers
3^2-x^2-9=0 5^2-x^2-9=0
there you go, now solve for x
(4,-4) 0
awesome, so your sol'ns for IV are : (-4,5) (0,3) (4,5)
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