Adding and Subtracting

• 1). Scan the problem to make sure they have like terms. (4.4x^2 + 4y - 6.798) + (4.32x - 2.25) cannot be solved since no terms have the same coefficients. (4.4x^2 + 4x) + (4.32x^2 - 2.25) can be solved, however, since you can work with the x^2s.
  
  
• 2). Add or subtract like terms. Adding the like x^2s in (4.4x^2 + 4x) + (4.32x^2 - 2.25) would be 4.4x^2 + 4.32x^2 = 4.72x^2. Don't forget to line up your decimals.
  
  
• 3). Drag down the remaining numbers. The final answer for (4.4x^2 + 4x) + (4.32x^2 - 2.25) is 4.72x^2 + 4x - 2.25.
  
  

Multiplying

• 1). Multiply decimal polynomials using the FOIL (first, outside, inside, last) method. For example, in (2.56x - .9)(-5.78x - 4.9), you would start by multiplying together the first terms in each polynomial, in this case 2.56x and -5.87x rounded to two decimal places equals -15.03x^2.
  
  
• 2). Multiply the inside terms. .9 X -5.78x = -5.2x.
  
  
• 3). Multiply the last terms. -.9 X -4.9 = 44.1
  
  
• 4). Use the rules of adding and subtracting polynomials to combine any answers from each step with like coefficients. Out of -15.03x^2, -12.54x, -52.x and 44.1, -12.54x and -52x share the same coefficient, x, so they should be added to get -64.54x.
  
  
• 5). Combine all terms to get a new polynomial. -15.03x^2 - 64.54x + 44.1.