Chap. 5 - Expressions, equations and linear relationships Flashcards
what is a open circle used for in an inequality graph?
< and >
what is a closed circle on an inequality graph used for?
⩽ and ⩾
what do you do if you multiply or divide by a negative in an inequality equation
flip the sign!
are inequalities written in ascending or descending order?
ascending
how do you do an inequality equation with two signs?
e.g 6-4<x>1.1*1.2</x>
every operation must be performed to ALL SECTIONS OF THE EQUATION.
e.g 6<x-4>1.1*1.2 - 4
you must get x in the middle by itself</x-4>
all lines can be expressed in the form of:
y=mx+c
m =
gradient
c =
y-intercept
left to right increasing line is a
positive gradient
left to right decreasing line is a
negative gradient
a horizontal line has
zero gradient
a vertical line has a
undefined gradient
finding the gradient of a line with two points is done by
y2-y1/x2-x1
to sketch lines, you need
the y and x intercept
the x intercept is found when y is ____ and the y intercept is found when x is ____.
0
how do you find the y-intercept of a line with 2 points?
sub in one of the points once you’ve found the gradient
what is the point-gradient formula?
y-y1=m(x-x1)
what do you need to do a point-gradient formula?
the gradient and one point
if the line has the same gradient then it’s
parallel
midpoint formula is
m=((x1 + x2)/2, (y1 + y2)/2)
distance formula is
√(x2-x1)^2+(y2-y1)^2
when is the substitution method best used?
when one of the equations has a pronumeral as the subject already
in a simultanous equation:
if the signs are different you can ____
if the signs are the same you can ____
add, subtract
if you can’t substitute and can’t eliminate:
look to multiply the equation. to eliminate, OR look to rearrange the equation to substitute
