How do you simplify #(4x^2 + 15x - 18) - (9x^2 - 5x + 19) - (-5x^2 + 18x - 20) - (-4x^2 - 7x + 15)#? Algebra Polynomials and Factoring Addition and Subtraction of Polynomials 1 Answer Don't Memorise Jun 18, 2015 #=color(red)(4x^2 ) + color(blue)(9x) -32# Explanation: #4x^2 + 15x - 18- 9x^2 + 5x -19 +5x^2 - 18x +20 +4x^2 +7x -15# Grouping like terms: #color(red)((4x^2 -9x^2+5x^2 +4x^2 ) ) + color(blue)((15x+5x-18x+7x)) + (-18 -19+20 -15)# #=color(red)(4x^2 ) +color(blue)(9x) -32# Answer link Related questions How do you add two polynomials? How do you subtract two polynomials? How do you add and simplify #3x^2-4x+7# and #2x^3-4x^2-6x+5#? How do you subtract #5b^2-2a^2# from #4a^2-8ab-9b^2#? How do you simplify #(6.9a^2-2.3b^2+2ab)+(3.1a-2.5b^2+b)#? How do you simplify #(-t+15t^2)-(5t^2+2t-9)#? How do you subtract #(-5m^2-m)-(3m^2+4m-5)#? How do you add two polynomials if they don't have like terms? How do you simplify #(3a+4b)-(-6a-3b)#? How do you subtract #(x^2-8x+7)-(6x^2+7x-3)#? See all questions in Addition and Subtraction of Polynomials Impact of this question 1596 views around the world You can reuse this answer Creative Commons License