Question

three questions?

Answer 1

Solve using elimination




Question 1

y=x^2
y= x + 2





Question 2

ToyA : y=48x+20
Toy B: y= -x^2 +200x+20






Question 3


Solve using substitution

y=3x-20
y= -x^2+34

Answer 2

@InstagramModel

Answer 3

ohh. I cannot do these :/

Answer 4

@InstagramModel ok

Answer 5

Q1: You are given 2 equations, both of which start out with "y=." Set one equation equal to the other (which will eliminate y). Your result?

Answer 6

And how do I do that @mathmale

Answer 7

y=x^2 (first equation)
y=x+2 (second one)
Set these equal to each other: y=x^2=x+1=y. We can now drop the 'y' and focus entirely on the 'x' ... in other words, we can solve for x.

x^2=x+1

Answer 8

Oh okay now solve x^2=x+1 ?

Answer 9

This is what we call a "quadratic equation." How do we go about solving a quadratic?

Answer 10

Your "solve x^2=x+1" could be better expressed in "standard form," which involves subtracting x+1 from both sides, so that all terms are on the left except for an '0 on the right. Try it.

Answer 11

Why is it a 1 instead of 2 for y=x+2

Answer 12

x^2−x−1=0

Answer 13

Let's rehash this a bit: "now solve x^2=x+1" .... subtract x+1 from both sides:

x^2-x-1=0. Is this much clear for you?

Answer 14

If so, what method or methods of solution would you try?

Answer 15

Yes it is :)

Answer 16

Is the answer x^2-x-1=0?

Answer 17

That's the standard form of the equation of a parabola / quadratic, yes, but we haven't yet "solved it for x." Our goal is to find the 2 x values that make this equation true.

Could you factor x^2-x-1=0?

Answer 18

Yes @mathmale

Answer 19

Can you finish this factoring? (x- )(x- ) Change one of the signs as necessary.

Answer 20

Okay @mathmale

Answer 21

x=1+5√/2,1−5√/2

Answer 22

Would like to see how you got that. But first, have you tried factoring? You have x^2-x-1, and that factors fairly easily into (x-2)( ?? ). Can you finish this?

Answer 23

Can you show me how to factor it please?

Answer 24

How embarrassing: I went off on a tangent there. You were correct in applying the quadratic formula here. I, too, get "radical 5" in both factors.

Answer 25

x^2-x-1=0 can be factored, but it's much easier to do what you've done: apply the quadratic formula.

Answer 26

Question 2 is approached in much the same way: consolidate all terms on the left side of the equation. Arrange the powers of x in descending order. Then consider which method of solution might work best.

Unfortunately, I need to get off the 'Net and join friends for breakfast. Hope these pointers are of help to you. Best wishes.