Learning Guide Learning Guide

146 • Chapter 5: Evaluation and SimplificationHere, you must subtract 17 from both sides of the equation. To doso, subtract the equation 17=17 from eq. Make sure to put parenthesesaround the unnamed equation.> eq - ( 17 = 17 );4 x = 6Now divide through by 4. Note that you do not have to use 4=4 inthis case.> % / 4;x = 3 2The following sections focus on more sophisticated manipulations.Expanding Polynomials as SumsSums are generally easier to comprehend than products, so you may find ituseful to expand a polynomial as a sum of products. The expand commandhas this capability.> poly := (x+1)*(x+2)*(x+5)*(x-3/2);poly := (x + 1) (x + 2) (x + 5) (x − 3 2 )> expand( poly );x 4 + 13 2 x3 + 5 x 2 − 31 2 x − 15The expand command expands the numerator of a rational expression.> expand( (x+1)*(y^2-2*y+1) / z / (y-1) );x y 2z (y − 1) − 2+1z (y − 1)x yz (y − 1) +xz (y − 1) + y 2z (y − 1) − 2yz (y − 1)