Math Analysis Review Packet Notes I Name: ____________________________ SOLVING EQUATIONS AND INEQUALITIES You must have a firm grasp on how to solve all types of equations. I expect that you already know how to solve one, two, and multi-step equations and will not provide notes on them here. Also, be sure you show each step of your work. NO WORK, NO CREDIT! Inequalities Don’t forget about working with inequalities. You need to remember to flip the inequality symbol when dividing by a negative. EX] 2x -18 x -9 DON’T FLIP EX] -2x -18 x 9 FLIP Absolute Value Equations EX] 2x + 3 = 5 2x + 3 = 5 2x = 2 x = 1 AND AND AND 2x + 3 = -5 Remember to set up 2 equations! 2x = -8 Subtract 3 from both sides x = - 4 Divide each side by 2 Radical Equations EX] 3 8x 3 5 2 Original Problem 3 8x 3 3 Isolate radical by adding 5 to both sides (3 8x 3 )3 (3)3 8x + 3 = 27 8x = 24 x=3 Cube each side Simplify Subtract 3 from both sides Divide both sides by 8 NOTE: Be sure that you check your solution(s)! This is one of the best ways to catch yourself making those silly little careless mistakes that drive you and your math teachers crazy! In the case of radical equations, your solutions may be extraneous. Math Analysis; updated 6/19/09 Page 1 SYSTEMS OF EQUATIONS You should know how to solve a system of equations in two-variables by graphing, substitution, linear combination (also called elimination), and matrices. Systems involving more than two variables are done using the calculator. NOTE: When solving systems, you can get one of the following answers: 1 solution (written as a coordinate point) infinitely many solutions no solution. SOLVING QUADRATIC EQUATIONS This single concept is the bulk of Algebra II. The terms roots, zeros, x-intercepts, and solutions are all synonymous. You should know how to solve quadratics by factoring, completing the square, and of course, the quadratic formula (please, please, please, memorize this!) x The quadratic formula: EX] EX] b b2 4ac 2a y = x2 – x – 6 y = (x + 2)(x – 3) Factor x+2=0 x = -2 Set each factor equal to 0 Solve x –3=0 x=3 y = x2 – x – 6 x x Let a = 1, b = -1, and c = -6 1 (1)2 4(1)(6) Substitute into quadratic formula 2(1) 1 x 1 24 1 25 = 2 2 1 5 6 3 2 2 AND = x 1 5 2 1 5 4 2 2 2 Simplify Simplify DON’T FORGET TO CHECK YOUR ANSWERS! Math Analysis; updated 6/19/09 Page 2 POLYNOMIAL FUNCTIONS The Rational Zero Theorem When solving polynomial equations, it is important to know the rational zero theorem: If f(x) = anxn + … + a1x + a0 has integer coefficients , then every rational zero has the form factors of constant term a0 p q factors of leading coefficient an EX] Find the rational zeros of f(x) = 3x3 – 4x2 – 17x + 6 Possible rational zeros: p factors of constant term, 6 ±1, 2, 3, 6 q factors of leading coefficient, 3 1, 3 Simplifying yields the following possibilities: 1, 2, 3, 6, 1 2 , 3 3 We then use either the calculator (look in the TABLE) or synthetic division to test the possible zeros. You may have to test several before you find one that works. Here, x = -2 works: -2 3 3 -4 -6 -10 -17 20 3 6 -6 Remember how to get the factor of f(x) from here? 0 Since x = -2 is a zero, then x + 2 is a factor of f. f(x) = (x + 2)(3x2 – 10x + 3) Factor original polynomial f(x) = (x + 2)(3x – 1)(x – 3) Factoring the trinomial Setting each factor equal to 0 and solving gives us the zeros. x+2=0 x = -2 3x – 1 = 0 x–3=0 3x = 1 x=3 The zeros are x = -2, x = Math Analysis; updated 6/19/09 1 , and x = 3 3 Page 3 Factor by Grouping Another skill to use when finding rational zeros of a polynomial function is factor by grouping. f(x) = 2x3 + 2x2 – 8x – 8 Original equation f(x) = 2x2(x + 1) – 8(x + 1) Factor GCF’s f(x) = (2x2 – 8)(x + 1) Rewrite f(x) =2(x2 – 4)(x + 1) Factor The zeros are –2, 2, and –1. NOTE: Be careful here! A common mistake is to forget the x2 – 4 = 0 x2 = 4 x=2 Writing Polynomial Equations from Zeros Given the zeros of a polynomial function, you should be able to write the equation of the original polynomial equation. The main thing here is to watch your signs! EX] The zeros of a polynomial function are –1, 5, and 6. Write the function of least degree. f(x) = (x + 1)(x – 5)(x – 6) f(x) = (x2 – 4x – 5) (x – 6) Use FOIL with first two terms f(x) = x3 – 4x2 – 5x – 6x2 + 24x + 30 Multiply f(x) = x3 – 10x2 + 19x + 30 Combine like terms NOTE: Use the TI-83 to check Math Analysis; updated 6/19/09 Page 4 Put original in Y1 and your answer in Y2 Look at your table of values – They should be the same! RATIONAL EXPRESSIONS I expect that you already know how to simplify rational expressions, as well as multiply and divide them. You need to know how to factor! Adding and subtracting rational expressions is just like adding and subtracting fractions – you must have the same denominator! EX] Add: 5 2 2 2 x 3x The LCD is 6x2 = 5(3 x ) 2(2) 2 2 x(3 x ) 3 x (2) Rewrite the fractions with LCD = 15 x 4 15 x 4 2 2 6x 6x 6x2 Simplify and add numerators SIMPLIFYING COMPLEX FRACTIONS Simplifying complex fractions just takes patience. You have to watch your algebra as you go through these kinds of problems. EX] Simplify 6 3 x 1 3 x 3( x 1) 6 6 3 x 1 x 1 ( x 1) = 3 3 x x Math Analysis; updated 6/19/09 Rewrite fractions in numerator with LCD (1) Page 5 = 3x 3 6 x 1 ( x 1) 3 x Distribute 9 3x x 1 = 3 x Simplify numerator 3(3 x ) ( x 1) = 3 x Factor numerator (2) (3) (4) = 3(3 x ) x ( x 1) 3 Multiply by reciprocal = x(3 x) ( x 1) Write in simplified form (5) NOTES: (6) 1) There is no need to distribute in line (6) above 2) There is more than one way to do this problem. I like to simplify the numerator as much as possible before I begin to work with the denominator. Math Analysis; updated 6/19/09 Page 6