((15-53y)/87)+53y=15
25-7a-{-6a+93-5-6a)}]
(15-53y/87)+53y=15
lim when x tends to infinity of x.e^(-x^2)
12x+2=6+6x
10-[-56+{-25+(-15)}]
53.1 x 10^9
0.30รท0.4
25-[-7a-{-6a+(3-5-)}]
(3-2i)x + (1+2i)y-1 =0
(3+2i)x - (1-2i) y-1 =0