First, rewrite the equation as:
#P_(SELL) = (26.65 * 26.65 * 17 * P_(SELL))/1.57 ->#
#P_(SELL) = (12073.7825 * P_(SELL))/1.57#
#P_(SELL) = 7690.31 * P_(SELL)#
Subtract #color(red)(P_(SELL))# from each side of the equation:
#P_(SELL) - color(red)(P_(SELL)) = 7690.31 * P_(SELL) - color(red)(P_(SELL))#
#0 = (7690.31 - 1)color(red)(P_(SELL))#
#0 = 7689.31 * color(red)(P_(SELL))#
Now, divide each side of the equation by #color(red)(7689.31)# to solve for #P_(SELL)#:
#0/color(red)(7689.31) = (7689.31 * P_(SELL))/color(red)(7689.31)#
#0 = (color(red)(cancel(color(black)(7689.31))) * P_(SELL))/cancel(color(red)(7689.31))#
#0 = P_(SELL)#
#P_(SELL) = 0#