FreeAlgebra                             Tutorials! Home Polynomials Finding the Greatest Common Factor Factoring Trinomials Absolute Value Function A Summary of Factoring Polynomials Solving Equations with One Radical Term Adding Fractions Subtracting Fractions The FOIL Method Graphing Compound Inequalities Solving Absolute Value Inequalities Adding and Subtracting Polynomials Using Slope Solving Quadratic Equations Factoring Multiplication Properties of Exponents Completing the Square Solving Systems of Equations by using the Substitution Method Combining Like Radical Terms Elimination Using Multiplication Solving Equations Pythagoras' Theorem 1 Finding the Least Common Multiples Multiplying and Dividing in Scientific Notation Adding and Subtracting Fractions Solving Quadratic Equations Adding and Subtracting Fractions Multiplication by 111 Adding Fractions Multiplying and Dividing Rational Numbers Multiplication by 50 Solving Linear Inequalities in One Variable Simplifying Cube Roots That Contain Integers Graphing Compound Inequalities Simple Trinomials as Products of Binomials Writing Linear Equations in Slope-Intercept Form Solving Linear Equations Lines and Equations The Intercepts of a Parabola Absolute Value Function Solving Equations Solving Compound Linear Inequalities Complex Numbers Factoring the Difference of Two Squares Multiplying and Dividing Rational Expressions Adding and Subtracting Radicals Multiplying and Dividing Signed Numbers Solving Systems of Equations Factoring Out the Opposite of the GCF Multiplying Special Polynomials Properties of Exponents Scientific Notation Multiplying Rational Expressions Adding and Subtracting Rational Expressions With Unlike Denominators Multiplication by 25 Decimals to Fractions Solving Quadratic Equations by Completing the Square Quotient Rule for Exponents Simplifying Square Roots Multiplying and Dividing Rational Expressions Independent, Inconsistent, and Dependent Systems of Equations Slopes Graphing Lines in the Coordinate Plane Graphing Functions Powers of Ten Zero Power Property of Exponents The Vertex of a Parabola Rationalizing the Denominator Test for Factorability for Quadratic Trinomials Trinomial Squares Solving Two-Step Equations Solving Linear Equations Containing Fractions Multiplying by 125 Exponent Properties Multiplying Fractions Adding and Subtracting Rational Expressions With the Same Denominator Quadratic Expressions - Completing Squares Adding and Subtracting Mixed Numbers with Different Denominators Solving a Formula for a Given Variable Factoring Trinomials Multiplying and Dividing Fractions Multiplying and Dividing Complex Numbers in Polar Form Power Equations and their Graphs Solving Linear Systems of Equations by Substitution Solving Polynomial Equations by Factoring Laws of Exponents index casa mÃ­o Systems of Linear Equations Properties of Rational Exponents Power of a Product and Power of a Quotient Factoring Differences of Perfect Squares Dividing Fractions Factoring a Polynomial by Finding the GCF Graphing Linear Equations Steps in Factoring Multiplication Property of Exponents Solving Systems of Linear Equations in Three Variables Solving Exponential Equations Finding the GCF of a Set of Monomials

Try the Free Math Solver or Scroll down to Tutorials!

 Depdendent Variable

 Number of equations to solve: 23456789
 Equ. #1:
 Equ. #2:

 Equ. #3:

 Equ. #4:

 Equ. #5:

 Equ. #6:

 Equ. #7:

 Equ. #8:

 Equ. #9:

 Solve for:

 Dependent Variable

 Number of inequalities to solve: 23456789
 Ineq. #1:
 Ineq. #2:

 Ineq. #3:

 Ineq. #4:

 Ineq. #5:

 Ineq. #6:

 Ineq. #7:

 Ineq. #8:

 Ineq. #9:

 Solve for:

 Please use this form if you would like to have this math solver on your website, free of charge. Name: Email: Your Website: Msg:

# Lines and Equations

Given the slope ,m, and a point P(x1 , y1) use the modified point-slope formula : y = m(x − x1 ) + y1

y = m(x − x1 ) + y1

⇒ Substitute the values for m and the point P(x1 , y1) then remove parentheses and collect like terms to find the equation in the y-intercept form:

y = mx +b

The modified point-slope form: y = m(x − x1 ) + y1 becomes the y-intercept form: y = mx +b where b = [ y1 − mx1 ]

Examples:

Write an equation of the line that contains the indicated point(s) and meets the indicated condition(s). Write the final answer in y-intercept form: y = mx +b

#1. P(0, 4), m = - 2; ⇒ y = mx + b for the slope (m) and y-intercept (b = y0).

Substituting directly : b = 4 y = (-2) x + (4) ∴ y = - 2x + 4

#2. P(- 2,- 4), m = 3/2; ⇒ y = m(x − x1 ) + y1 m = 3/2 and P(x1 , y1) → x1 = - 2, y1= - 4

⇒ y = 3/2 [x − (- 2)]+ (- 4) or y = 3/2 x + [(3/2)(+2)+ (-4)] or y = 3/2 x + [ 3 − 4]

∴ y = 3/2 x â€“1 b = - 1

#3. P(-2,-3); m = 0 [horizontal] (y = b) Lines that are horizontal go through y = y1 ∴ y = - 3

#4. Given points: (3, 2), (5, - 3) Find Dy and Dx directly from the table or the points. m = - 5/2 x1=3, y1=2 ⇒ y = -5/2 [x - (3)] + (2) or b = 19/2 . ∴ y = - 5/2 x + 19/2

#5. Graph , for b = -3, b = 0, b = 3 or b = {-3, 0, 3} on the same coordinate system. Plot each y-intercept (0,b) and use the slope m = -1/2 to graph the lines.

The lines have the same slope so they are parallel.

 All Right Reserved. Copyright 2005-2019