DECKS 1&2 COMBINED Flashcards
What is a solution to an equation?
A solution is the set of values that makes an equation TRUE.
How can you tell if the point (5, -3) is a solution to a linear equation?
If it “works.” Sub 5 in for the X and -3 in for the Y. Simplify. If the statement is true, then it is a solution. If it is a solution, then it is on the line.
What are the slopes of the diagonals of a square?
+1 going up L to R, and -1 going down from L to ROW
What is the equation of the y axis?
x=0
Describe what the line y=x looks line
positive diagonal line from bottom left to upper right, slope of 1, through the origin
How can you think of the points on the line y=-x to help you graph it?
the x values are opposite the y values… so (2, -2) and (-2, 2) and (-107, 107).
What is the slope formula you use when trying to find the slope if you are given two points?
m = ( y - y ) / ( x - x )
What is the slope of a vertical line?
undefined
when you see “ - y” or “ - x” what can you think of?
opposite of y and opposite of x
Parallel lines have ______ slopes, or slopes
the same
y = 1/2 x - 8 what is the slope?
1/2
If a line as a slope of 2/3, then any line parallel to it will have a slope of ___ and any line perpendicular to it will have a slope of ___
parallel 2/3 and perp -3/2
y=mx+b what form?
slope intercept
what does a slope of zero look like?
horizontal, flat from left to right. The x axis has a slope of zero.
If you are given two points and need to find the equation of a line, how do you do it?
First, fine the slope using m=(y-y)/(x-x), then use that slope and EITHER OF THE POINTS. Put it in point slope form.
what does a slope that is undefined look like?
vertical, straight up and down. The y axis has a slope of zero.
What is the equation of the x axis?
y=0
What is the x intercept of a line? (what are the coordinates?)
Where the line crosses the horizontal axis, the x axis. The coordinates are ( x, 0 )
How do a lot of people think about the slope (the slope)?
rise/run… or change in y / change in x
The three forms of equations of a line we use are :
point-slope, slope-intercept, standard
what is the origin?
the point (0,0)
perpendicular lines have _____
opposite AND reciprocal slopes
(switch sign and flip the fraction)
What do you know about all Y intercepts?
(0,y) they have an x coordinate of ZERO
Why is it called “slope-intercept” form?
There is a slope and an intercept explicitly shown in the formula
if a slope of zero is 0 degrees, what is a slope of -1?
-45 degrees downhill (traveling L to R)
How can you find the slope if it is in standard form?
Solve for y and change it into slope intercept form.
parallel lines have ______
the same slope
How can you find the x intercepts from an equation of a line?
Plug zero in for Y, and solve for X. The coordinates will be ( X, 0)
What is the “point slope” form?
y-y = m (x-x) (has a point and a slope in it)
How can you tell if the point (5, -3) is on a line if you are given the equation?
If it “works.” Sub 5 in for the X and -3 in for the Y. Simplify. If the statement is true, then it is a solution. If it is a solution, then it is on the line.
how can you think of the points on the line y=x to help you graph it?
all of the x values are equal to all of the y values.. so (2,2), (3,3), (5,5), (-100,-100) are all in the solution set and on the line
What is the graph of a line showing us?
It is showing us all of the points, (x,y), that make the equation true. Every dot on the graphed line will make the equation true, they all work.
what is the “most popular” form?
slope intercept y=mx+b
When you graph a line, what is it?
It is a bunch of points!!! all have coordinates (x,y) it is the solution set, all of the coordinates that WORK in the equation.
4x - 7y = 28 what is x intercept?
plug 0 in for y, 28/4=8, so (8,0)
What do you know about all X-intercepts?
they have a y coordinate of ZERO (x,0)
If we are given a Y value, like y=8, and need to find the x that goes with it, how do you do it?
substitute the 8 in for the y in the equation and solve for x. That x goes with the 8. the point (x, 8) will be on the line.
what are the coordinates of a point?
(x,y), the x and y value.