a) 36-9x+27x+15= 54+18x
b)43x-8y+2-24x+18x-9=37x-8y-7
c)√20a -3√200b-3√125b+√700a=2√5a -30√2b-15√5b+10√7a=
=2√5a -30√2b-15√5b+10√7a=
d)√2197x+10+3√52-7-2√208x=13√13x+10+6√13-7-8√13x=
=5√13x+3+6√13
e)3x²+6+5x+(-9x²)-4x-12=3x²+6+5x-9x²-4x-12=-6x²+x-6
f)14x²+7+3x+(-9x²)-6x-15=14x²+7+3x-9x²-6x-15=5x²-3x-8