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### Course: Grade 8 (Virginia)>Unit 4

Lesson 2: Graphing slope-intercept form

# Graphing lines from slope-intercept form review

Slope intercept form is y=mx+b, where m is slope and b is the y-intercept. We can use this form of a linear equation to draw the graph of that equation on the x-y coordinate plane.
Slope intercept form is y, equals, m, x, plus, b, where m is slope and b is the y-intercept.
Slope-intercept form is nice when you're drawing graphs.
For example, imagine we're given the equation y, equals, 2, x, plus, 7 and asked to graph it.
Straight from the equation, we know the y-intercept is 7.
And we know the slope is 2.
start text, S, l, o, p, e, end text, equals, start fraction, delta, y, divided by, delta, x, end fraction, equals, start fraction, 2, divided by, 1, end fraction, equals, 2
So, for every one unit we go to the right, we must go up two units:
Here is our final graph:

## Practice

Problem 1
• Current
Graph the following equation.
y, equals, minus, 4, x, minus, 1

Want more practice? Check out this exercise.

## Want to join the conversation?

• i do not like this at all..
• This is the start of the largest empire of the world called math. This is important. If you don’t like it but want to work in any field related to math or science you will have a hard time. Revise it. Try to see the beauty of math. I would recommend Vi Harts videos
• i need help beause i do not really under stand
• Eg. Equation: y=2x-4

Let x be 0, y= 2*0-4= 0-4= -4
Let x be 1, y= 2*1-4= 2-4= -2
Let x be 2, y= 2*2-4= 4-4= 0 and so on...

Then we get points: (0,-4), (1,-2), (2,0), ...
-----------------------------------------------------
Eg. Equation: y=(3/2)x-4

If x is 0, then y=(3/2)*0-4= 0 -4= -4
If x is 1, then y=(3/2)*1-4= 1.5-4= -2.5
If x is 2, then y=(3/2)*2-4= 3 -4= -1 and so on...

So we get points: (0,-4), (1,-2.5), (2,-1), ...
• math people... how do they get this stuff
• i know right is kinda hard
• when will we use this in our daily lives
• never
• I am so confused with the whole rise over run! it really is messing with my brain. I am so confused not just by the equation but I don't have a teacher to help me / guid me through this. And I don't have anyone to talk to help either. SO PLEASE HELP ME!
• Slope means how steep a line is. We know how steep a mountain is judging on how vertical it is. Similar to slope of lines. We judge it by how vertical it is and how much it increases in the vertical direction when compared to the horizantal direction. That's where rise over run came from.

Excellent question, by the way.
• Khan Academy has done me so much help with school, you don't know man :)