\(\frac{2x}{x-14}-\frac{12x}{2x-28}=0\)
a,\(\frac{\frac{2}{3}+\frac{2}{7}-\frac{1}{14}}{-1-\frac{3}{7}+\frac{3}{28}}\)
b,\(\left(x+\frac{1}{2}\right).\left(\frac{2}{3}-2x\right)=0\)
a) \(\frac{\frac{2}{3}+\frac{2}{7}-\frac{1}{14}}{-1-\frac{3}{7}+\frac{3}{28}}=\frac{\frac{37}{42}}{\frac{-37}{28}}=\frac{37}{42}.\frac{28}{-37}=\frac{-2}{3}\)
b) \(\left(x+\frac{1}{2}\right).\left(\frac{2}{3}-2x\right)=0\)
\(\Leftrightarrow\orbr{\begin{cases}x+\frac{1}{2}=0\\\frac{2}{3}-2x=0\end{cases}}\)
\(\Leftrightarrow\orbr{\begin{cases}x=0-\frac{1}{2}=\frac{-1}{2}\\x=\left(\frac{2}{3}-0\right):2=\frac{1}{3}\end{cases}}\)
Vậy \(x\in\left\{\frac{-1}{2};\frac{1}{3}\right\}\)
a,\(\frac{\frac{2}{3}+\frac{2}{7}-\frac{1}{14}}{-1-\frac{3}{7}+\frac{3}{28}}=\frac{2.\left(\frac{1}{3}+\frac{1}{7}-\frac{1}{28}\right)}{3.\left(-\frac{1}{3}-\frac{3}{7}+\frac{1}{28}\right)}=\frac{-2}{3}\)
cách này k cần dùng máy tính (hok tốt)
b,\(\left(x+\frac{1}{2}\right).\left(\frac{2}{3}-2x\right)=0\)
\(\Rightarrow\orbr{\begin{cases}x+\frac{1}{2}=0\\\frac{2}{3}-2x=0\end{cases}\Rightarrow\orbr{\begin{cases}x=-\frac{1}{2}\\x=\frac{1}{3}\end{cases}}}\)
Vậy....
1 . \(\frac{x-1}{12}-\frac{2x-12}{14}=\frac{3x-14}{25}-\frac{3x-12}{27}\)
2 . \(\frac{2x-1}{2}+\frac{2x+1}{3}=\frac{2x+7}{6}+\frac{2x+9}{7}\)
3 . \(\frac{x^2+x+4}{2}+\frac{x^2+x+7}{3}=\frac{x^2+x+13}{5}+\frac{x^2+x+16}{6}\)
4 . \(\frac{201-x}{99}+\frac{203-x}{97}+\frac{205-x}{95}+3=0\)
Giải các phương trình sau bằng cách đưa về dạng ax + b = 0:
\(a,\frac{\left(2x+1\right)^2}{5}-\frac{\left(x-1\right)^2}{3}=\frac{7x^2-14x-5}{15}\)
\(b,\frac{x+1}{3}+\frac{3\left(2x+1\right)}{4}=\frac{2x+3\left(x+1\right)}{6}+\frac{7+12x}{12}\)
giải các phương trình
a.\(2x^2+3=2x\left[x+4\right]-7\)7
b.\(4x^2-12x+5=0\)
c.\(|5-2x|=1-x\)
d.\(\frac{2}{x-1}=\frac{(2x-1).(2x+1)}{x^3-1}-\frac{2x+3}{x^2+x+1}\)
a) 2x^2 + 3 = 2x(x + 4) - 7
<=> 2x^2 + 3 = 2x^2 + 8x - 7
<=> 2x^2 - 2x^2 - 8x = - 7 - 3
<=> -8x = -10
<=> x = -10/-8 = 5/4
b) 4x^2 - 12x + 5 = 0
<=> 4x^2 - 2x - 10x + 5 = 0
<=> 2x(2x - 1) - 5(2x - 1) = 0
<=> (2x - 5)(2x - 1) = 0
<=> 2x - 5 = 0 hoặc 2x - 1 = 0
<=> x = 5/2 hoặc x = 1/2
c) |5 - 2x| = 1 - x
<=> \(\hept{\begin{cases}5-2x\text{ nếu }5-2x\ge0\Leftrightarrow x\ge\frac{5}{2}\\-\left(5-2x\right)\text{ nếu }5-2x< 0\Leftrightarrow x< \frac{5}{2}\end{cases}}\)
+) nếu x >= 5/2, ta có:
5 - 2x = 1 - x
<=> -2x + 1 = 1 - 5
<=> -x = -4
<=> x = 4 (tm)
+) nếu x < 5/2, ta có:
-(5 - 2x) = 1 - x
<=> -5 + 2x = 1 - x
<=> 2x + 1 = 1 + 5
<=> 3x = 6
<=> x = 2 (ktm)
d) \(\frac{2}{x-1}=\frac{\left(2x-1\right)\left(2x+1\right)}{x^3-1}-\frac{2x+3}{x^2+x+1}\) ; ĐKXĐ: x # 1
<=> \(\frac{2}{x-1}=\frac{\left(2x-1\right)\left(2x+1\right)}{\left(x-1\right)\left(x^2+x+1\right)}-\frac{2x+3}{x^2+x+1}\)
<=> \(\frac{2\left(x^2+x+1\right)}{\left(x-1\right)\left(x^2+x+1\right)}=\frac{\left(2x-1\right)\left(2x+1\right)}{\left(x-1\right)\left(x^2+x+1\right)}-\frac{\left(2x+3\right)\left(x-1\right)}{\left(x-1\right)\left(x^2+x+1\right)}\)
<=> 2(x^2 + x + 1) = (2x - 1)(2x + 1) - (2x + 3)(x - 1)
<=> 2x^2 + 2x + 2 = 2x^2 - x + 2
<=> 2x^2 - 2x^2 + 2x - x = 2 - 2
<=> x = 0
mạn phép vô đây để kiếm câu trả lời
\(2x^2+3=2x\left(x+4\right)-7\)
\(< =>2x^2+3=2x.x+4.2x-7\)
\(< =>2x^2+3=2x^2+8x-7\)
\(< =>2x^2+3-2x^2=8x-7\)
\(< =>\left(2x^2-2x^2\right)-8x=-7-3\)
\(< =>-8x=-10< =>8x=10\)
\(< =>x=10:8=\frac{10}{8}=\frac{5}{4}\)
\(4x^2-12x+5=0\)
\(< =>4x^2-2x-10x+5=0\)
\(< =>2x\left(2x-1\right)-5\left(2x-1\right)=0\)
\(< =>\left(2x-1\right)\left(2x-5\right)=0\)
\(< =>\orbr{\begin{cases}2x-1=0\\2x-5=0\end{cases}}< =>\orbr{\begin{cases}2x=1\\2x=5\end{cases}}\)
\(< =>\orbr{\begin{cases}x=1:2=\frac{1}{2}\\x=5:2=\frac{5}{2}\end{cases}}\)
a) x + 5x5x > 0
b) 6x2−16x2−1 + 5 = 8x−14x+4−12x−14−4x8x−14x+4−12x−14−4x
c) (x2 - 2x)(x3 - 3x2 - 18x) = 0
d) x+112−x−16>x−28−x+38x+112−x−16>x−28−x+38
e) / 2x-3/ = x-1
f) /x-5/-5=7
TÍNH A:
\(\frac{12x+4}{4x+28}=\frac{A}{2x^2+8x-21}\)
\(\frac{x^2+4x+4}{x^2-4}=\frac{x^2+3x+2}{A}\)
help me ai nhanh mk k cho
Giải các phương trình sau:
\(\frac{3}{4x-20}-\frac{15}{2x^2-50}+\frac{7}{6x+30}=0\)
\(\frac{8x^2}{3-12x^2}+\frac{1+8x}{4+8x}=\frac{-2x}{3-6x}\)
\(\frac{1}{x^2-2x+1}+\frac{1}{x^2+2x=1}=\frac{2}{x^2-1}\)
\(\frac{1}{x^2+1}+\frac{1}{x^2+3x+2}+\frac{1}{x^2+5x+6}+\frac{1}{x^2+7x+12}=\frac{4}{5}\)
Bài 1:Tìm x biết
1.\(\frac{2}{3}\sqrt{12x}+\sqrt{12x}-9=\frac{1}{3}\sqrt{3x}\)
2.\(\sqrt{2x}-3\sqrt{8x}+4\sqrt{18x}=14\)
1) ĐK: \(x\ge0\)
PT \(\Leftrightarrow\frac{2}{3}\sqrt{12x}+\sqrt{12x}-\frac{1}{3}\sqrt{3x}=9\)
\(\Leftrightarrow\frac{5}{3}\sqrt{12x}-\frac{1}{3}\sqrt{3x}=9\)
\(\Leftrightarrow3\sqrt{3x}=9\) \(\Leftrightarrow x=3\left(TM\right)\)
Vậy \(x=3\)
2) ĐK: \(x\ge0\)
PT \(\Leftrightarrow7\sqrt{2x}=14\) \(\Leftrightarrow x=2\left(TM\right)\)
Vậy \(x=2\)