Understanding Algebra: A Beginner's Guide

A variable is an unknown number.

2x+5=15

An expression includes variables, numbers and operators x+3

An equation includes = sign x+3 = 0

Inequalities means not equal.

x > 5 x < 2

Solving inequalities

−2x/−2<6/−2

Answer: x > 3

If you're multiplying or dividing by a negative number, need to flip the ineuqlity sign.

Quadtric equations

ax2+bx+c=0

cubic equations

x3+2x+5=0

Solving quadtric equations

Method 1: Put into two brackets. x2 - 5x + 6 = 0

(x - 2)(x - 3) = 0 x-2 = 0 x- 3 = 0

Answer: x=2 or x=3

Method 2: Use the following equation

Exponents and Powers

Logarithm

Opposite of exponents.

if 23=8 , logarithm means what power 2 must be raised to, to get 8

log2(8)=3

Polynomial

All polynormials are expressions. But all expressions are not polynormials.

Matrix

Matrix Operations:

1. Must be the same size to add/ subtract

2. Multiplying - multiply rows of first matrix with columns of second matrix

Determinant of square matrix

A - [a b c d] det (A) = (a*d) - (b * c)