Algebra/Trig Review - Pauls Online Math Notes - Lamar University

Algebra/Trig ReviewRemember that you are being asked to solve this not simplify it! Therefore, makesure that you don’t just cancel an x out of both sides! If you cancel an x out as thiswill cause you to miss x = 0 as one of the solutions! This is one of the more commonmistakes that people make in solving equations.2.23x− 16x+ 1 = 0SolutionIn this case the equation won’t factor so we’ll need to resort to the quadratic formula.Recall that if we have a quadratic in standard form,2ax + bx + c = 0the solution is,2− b ± b −4acx =2aSo, the solution to this equation is2( 16) ( 16) 4( 3)( 1)23 ( )− − ± − −x =16 ± 244=616 ± 2 61=68 ± 61=3Do not forget about the quadratic formula! Many of the problems that you’ll beasked to work in a Calculus class don’t require it to make the work go a little easier,but you will run across it often enough that you’ll need to make sure that you can useit when you need to. In my class I make sure that the occasional problem requiresthis to make sure you don’t get too locked into “nice” answers.3.x2− 8x+ 21 = 0SolutionAgain, we’ll need to use the quadratic formula for this one.8 ± 64 −4( 1)( 21)x =28 ± −20=28±2 5i=2= 4±5i© 2006 Paul Dawkins 30http://tutorial.math.lamar.edu/terms.aspx