Tolong dijawab no 6-10 pakai cara bsk dikumpul

6. 7x -15 -2x +10
= 5x -5

7. 2x² -15y +8 -3x² -4y -3
= -x² -19y +5

8. 5x +5y -10 -8x -3y +4
= -3x -2y -6

9. 2x² +3x +y -4x² -2x +8
= -2x² +x +y +8

10. 8 -5x +4y -4x -3y +2
= -9x +y +10