4. Efectuați calculele: x²-8x+16 x²-2x-8 x²+6x+9 x²-10x+24 a) : Sr-15 x²-x-6 x²+7x+12 x²-16 c) x²-25 e) x²-9 x²+7x+12 x²+6x+9 x²+12x+32 x²+11x+28 -: 2 x²+8x+15 x² +16x+64 x² -64 -4x+4x²-6x+8 x²-25 x²-8x+15 x²-x-12 x²+9x+20x+7x+12​