(x+5)(5a+1)-(х+5)(2а-8)
X*5a+x*1+5*5a+5*1-x*2a+x*8+5*2a+8*(-8)=5ax+x+25a+5-2ax+8x+10a-64=5ax-2ax+x+8x+25a-64=3ax+9x+25a-64
(х+5)*(5а+1)-(х+5)*(2а-8) (х+5)*(5а+1-(2а-8)) (х+5)*(5а+1-2а+8) (х+5)*(3а+9) (х+5)*3(а+3)