SOLUTION: how do I write an equation in slope intercept form that contains the origin and has a slope of -2

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Question 686743: how do I write an equation in slope intercept form that contains the origin and has a slope of -2
Found 2 solutions by jim_thompson5910, MathLover1:
Answer by jim_thompson5910(35256) (Show Source):
You can put this solution on YOUR website!
y = mx + b

y = -2x + b

0 = -2(0) + b

0 = 0 + b

0 = b

b = 0

So the equation is y = -2x

Answer by MathLover1(20849) (Show Source):
You can put this solution on YOUR website!

given:
a slope and origin (,)

Solved by pluggable solver: FIND a line by slope and one point

What we know about the line whose equation we are trying to find out:

it goes through point (0, 0)

it has a slope of -2

First, let's draw a diagram of the coordinate system with point (0, 0) plotted with a little blue dot:

Write this down: the formula for the equation, given point and intercept a, is

(see a paragraph below explaining why this formula is correct)

Given that a=-2, and , we have the equation of the line:

Explanation: Why did we use formula ? Explanation goes here. We are trying to find equation y=ax+b. The value of slope (a) is already given to us. We need to find b. If a point (, ) lies on the line, it means that it satisfies the equation of the line. So, our equation holds for (, ): Here, we know a, , and , and do not know b. It is easy to find out: . So, then, the equation of the line is: .

Here's the graph: