Formulas to Know (precal)

Ordered Pair

(x,y)

Distance Formula

√(x-x₁)²+(y-y₁)²

Midpoint Formula

(x₁+x₂/2 , y₁+y₂/2)

Slope

y₂-y₁/ x₂-x₁

Parallel Lines

same slope

Perpendicular Lines

opposite recipricol slope

Quadratic Formula

-b±√b²-4(a)(c)/ 2(a)

Discriminant

b²-4(a)(c)

Vertical Line

x=#

Horizontal Line

y=#

Point Slope Form of Line

y-y₁=m(x-x₁)

General Form of Line

Ax+By=c

Slope Intercept Form of Line

y=mx+b

Standard Form of Circle

(x-h)²+(y-k)²+r²

Unit Circle

x²+y²=1

General form of Circle

x²+y²+ax+by+c=0