Brittany's Brilliant Equations

Linear Equations

5n+11=7n+9	equation
SOLUTION
5n+11=7n-9	write original equation
11=2n-9	subtract 5n from each side
20=2n	add 9 to each side
10=n	divide each side by 2

Literal Equations

P=2l+2w solve for w	Equation
SOLUTION
P=2l+w	Write perimeter formula
P-2l=w	Subtract 2l from each side
P-2l=w   2	Divide each side by 2

EQUATION FOR A LINE

Slope intercept form
                y=mx+b
Point Slope form
                y-y₁=m(x-x₁)
Two Points (Slope)
                m=y₂-y_1/x2-x1

_{Point Slope
y-y1=m(x-x1)  Let (x1,y1)=(2,3) m=-1/2
y-3=-1/2(x-2) substitute for m,x, & x2
After you have used the point slope form to find the equation, you can simplify the result into slope intercept form.
y-3=-1/2(x-2)   write point slope form
y-3=-1/2x+1      distributive property
y=-1/2x+4 write in slope intercept form}

_{Two Points (Slope)   (2,4) (3,6)
m=y2-y1/x2-x1
m=6-4   = m=2/1 = 2
    3-2}

 
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