$\frac{2}{x-14}$ – $\frac{5}{x-13}$ =$\frac{2}{x-9}$ -$\frac{5}{x-11}$ 03/07/2021 Bởi Serenity $\frac{2}{x-14}$ – $\frac{5}{x-13}$ =$\frac{2}{x-9}$ -$\frac{5}{x-11}$
Đáp án:17 Giải thích các bước giải: 2/x-14-5/x-13=-3x-44/(x-14)(x-13) 2/x-9-5/x-11=3x-23/(x-11)(x-9) -3x-44/(x-14)(x-13)=-3x-23/(x-11)(x-9) 2/x-14-5/x-13=2/x-9-5/x-11 -2/x-9+5/x-11-5/x-13+2/x-14=0 -10(x-17)/(x-14)(x-13)(x-11)(x-9)=0 1/x-14=0 1/x-13=0 1/x-11=0 1/x-9=o => 17 Bình luận
Đáp án: 2/(x-14)-5/(x-13)=2/(x-9)-5/(x-11) => 2(x-13)(x-9)(x-11)-5(x-14)(x-9)(x-11)=2(x-14)(x-13)(x-11) => (2x-26)(x-9)(x-11)-(5x-70)(x-9)(x-11)=(2x-28)(x-13)(x-11) => (2x²-18x-26x+234)(x-11)-(5x²-45x-70x+630)(x-11)=(2x²-26x-28x+364)(x-11) => (2x²-44x+234)(x-11)-(5x²-115x+630)(x-11)=(2x²-54x+364)(x-11) => 2x³-22x²-44x²+484x+234x-2574-(5x³-55x²-115x²+1265x+630x-6930)=(2x³-22x²-54x²+594x+364x-4004) => 2x³-22x²-44x²+484x+234x-2574-5x³+55x²+115x²-1265x-630x+6930-2x³+22x²+54x²-594x -364x+4004 => -5x³+158x²-2135x+8360=0 => x=6,2 và x=12,7 và x=12,7 (mode 5->4) Vậy S={6,2;12,7} Bình luận
Đáp án:17
Giải thích các bước giải:
2/x-14-5/x-13=-3x-44/(x-14)(x-13)
2/x-9-5/x-11=3x-23/(x-11)(x-9)
-3x-44/(x-14)(x-13)=-3x-23/(x-11)(x-9)
2/x-14-5/x-13=2/x-9-5/x-11
-2/x-9+5/x-11-5/x-13+2/x-14=0
-10(x-17)/(x-14)(x-13)(x-11)(x-9)=0
1/x-14=0
1/x-13=0
1/x-11=0
1/x-9=o
=> 17
Đáp án:
2/(x-14)-5/(x-13)=2/(x-9)-5/(x-11)
=> 2(x-13)(x-9)(x-11)-5(x-14)(x-9)(x-11)=2(x-14)(x-13)(x-11)
=> (2x-26)(x-9)(x-11)-(5x-70)(x-9)(x-11)=(2x-28)(x-13)(x-11)
=> (2x²-18x-26x+234)(x-11)-(5x²-45x-70x+630)(x-11)=(2x²-26x-28x+364)(x-11)
=> (2x²-44x+234)(x-11)-(5x²-115x+630)(x-11)=(2x²-54x+364)(x-11)
=> 2x³-22x²-44x²+484x+234x-2574-(5x³-55x²-115x²+1265x+630x-6930)=(2x³-22x²-54x²+594x+364x-4004)
=> 2x³-22x²-44x²+484x+234x-2574-5x³+55x²+115x²-1265x-630x+6930-2x³+22x²+54x²-594x -364x+4004
=> -5x³+158x²-2135x+8360=0
=> x=6,2 và x=12,7 và x=12,7 (mode 5->4)
Vậy S={6,2;12,7}