a) 2x la puterea 2 -10x+3x-15=2xla puterea 2 -7x-15
b) 8x la puterea 2 +12xy-15y la puterea 2=8x la puterea 2 +2xy-15y la puterea 2
c) 6x la puterea 3 +4xy-3xla puterea 2y -2y la puterea 2
d) 2x la puterea 2 +5xy-6xy-15y la puterea 2= 2x la puterea 2 -xy-15y la puterea 2