1. 3x – 7 X + 1
——— + ——- = – 16
2 3
2. X – x + 1 2x + 1
——— = ———
3 5
3. 2x – 1 5x + 2
——— – ———- = x + 13
3 7
4. 3(x + 3) 1 5x + 9. 7x – 9
———– + – = ——— – ———–
4 2 3 4
1. 3x – 7 X + 1 ——— + ——- = – 16 2 3 2. X – x + 1 2x + 1 ——— = ——— 3
By Eva
Đáp án:
Giải thích các bước giải:
1, 3x-7 /2 + x+1 /3 =-16 9x-21 /6 +2x+2 /6 =-96/6 suy ra 9x-21+2x+2 =-96 11x =-77 x=-7 2, 5(x-x+1) /15 =3(2x+1) /15 5x-5x+5 /15 =6x +3 /15 suy ra 5x-5x +5=6x+3 -6x=-2 nên x=1/3 3) 7(2x-1) /21 -3(5x+2) /21=21(x+13) /21 suy ra 14x-7 -15x-6 =21x +273 -22x =286 nên x=-13 4) 9(x+3) /12 +6/12 =4(5x+9) /12 -3(7x-9) /12 suy ra 9x+27 +6 =20x+36 -21x+27 10x =36 nên x=18/5 OK