Question Number 39058 by jasno91 last updated on 02/Jul/18
Commented by maxmathsup by imad last updated on 25/Jul/18
$${if}\:{you}\:{want}\:{developpement}\:{let} \\ $$$${A}\left({x}\right)=\left(\mathrm{5}{x}−\mathrm{3}\right)\left({x}+\mathrm{4}\right)−\left(\mathrm{2}{x}+\mathrm{5}\right)\left(\mathrm{3}{x}−\mathrm{4}\right) \\ $$$${A}\left({x}\right)=\mathrm{5}{x}^{\mathrm{2}} \:+\mathrm{20}{x}\:−\mathrm{3}{x}\:−\mathrm{12}\:−\left(\mathrm{6}{x}^{\mathrm{2}} \:−\mathrm{8}{x}\:+\mathrm{15}{x}\:−\mathrm{20}\right) \\ $$$$=\mathrm{5}{x}^{\mathrm{2}} \:+\mathrm{17}{x}\:−\mathrm{12}\:−\mathrm{6}{x}^{\mathrm{2}} \:−\mathrm{7}{x}\:+\mathrm{20} \\ $$$$=−{x}^{\mathrm{2}} \:+\mathrm{10}{x}\:+\mathrm{8} \\ $$
Answered by $@ty@m last updated on 02/Jul/18
