Y = 4x – 18
y = -5x +9

(3, -6)

General Formulas and Concepts:

Pre-Algebra

Order of Operations: BPEMDAS

Brackets Parenthesis Exponents Multiplication Division Addition Subtraction Left to Right  

Equality Properties

Multiplication Property of Equality Division Property of Equality Addition Property of Equality Subtraction Property of Equality

Algebra I

Coordinates (x, y)Terms/CoefficientsSolving systems of equations using substitution/elimination

Step-by-step explanation:

Step 1: Define Systems

y = 4x - 18

y = -5x + 9

Step 2: Solve for x

Substitution

Substitute in y [2nd Equation]:                                                                           4x - 18 = -5x + 9[Addition Property of Equality] Add 5x on both sides:                                   9x - 18 = 9[Addition Property of Equality] Add 18 on both sides:                                   9x = 27[Division Property of Equality] Divide 9 on both sides:                                  x = 3

Step 3: Solve for y

Substitute in x [1st Equation]:                                                                           y = 4(3) - 18Multiply:                                                                                                             y = 12 - 18Subtract:                                                                                                            y = -6

The answer is