Going through my substitution section of my homework, and I successfully did most of them but had trouble with two of them:
Determine the intersection of the following systems:
a) y = 2x – 7 and y = - x2 -4 x – 3
Heres my attempt:
In every other question we've had we could just simplify this last step to end up with an answer like (x-x)(x-x), however with this one I can't see what multiplies to -4, and adds to 6
Then there's the second one
b) x2 + y2 = 30 and 2 x – 3 y = 10
2x-3y=10 ~ y= 2x + 10
x2 +(2x + 10)2 = 30
.........3......3 [sorry about dots, still learning how to type in equations]
Is this correct so far? It doesn't feel like it is....
For quadratic equations you can find the zeros by the following methods (in order of decreasing difficulty): Rational Root Theorem, Factoring, Completing the Square, Quadratic Equation.
It's useful to know all 4.
For problem 1, completing the square you arrive at +/- sqrt(13)-3
Problem 2, you seem to be doing it right. Squaring that linear expression gives you a trinomial of the 2nd degree. Combine terms. Use quadratic equations if it's messy.
topsquark I will check that out tomorrow, I have to go to bed right now, so I'm not going to be able to do it now.
For now I'll just clean it up by posting a picture, hopefully if someone answers I can check it in the morning before my test.
Can anyone solve this for me? This is a sample question for my quiz tomorrow that I'm still not ready for, could really, really use an answer.