Выражения: 3c+a/4c - a-7c/4c 2p/p+3 + 3-p/p+3 x^2/x-4 + 4x/4-x m/m^2-n^2 - n/m^2-n^2

(3c+a)/4c - (a-7c)/4c=(3c+a- a+7c)/4c=4с/4с=1
2p/(p+3) + (3-p)/(p+3)=(2p+3-p)/(p+3)=(p+3)/(p+3)=1
x²/(x-4) + 4x/(4-x)=x²/(x-4) - 4x/(х-4)=(x² - 4x)/(х-4)=х(х-4)/(х-4)=х
m/(m²-n²) - n/(m²-n²)=(m- n)/(m-n)(m+n)=1/(m+n)