a, 4(5x-3)-3(2x+1)=9
b, |x-9|=2x+5
c, \(\dfrac{2}{x-3}+\dfrac{3}{x+3}=\dfrac{3x+5}{x^2-9}\)
Giải phương trình sau :
a,\(\dfrac{7-3x}{12}+\dfrac{5x+2}{7}=x+13\)
b,\(\dfrac{3\left(x+3\right)}{4}-\dfrac{1}{2}=\dfrac{5x+9}{7}-\dfrac{7x-9}{4}\)
c,\(\dfrac{2x+1}{3}-\dfrac{5x+2}{7}=x+3\)
d,\(\dfrac{2x-3}{3}-\dfrac{2x+3}{7}=\dfrac{4x+3}{5}-17\)
a: \(\Leftrightarrow7\left(7-3x\right)+12\left(5x+2\right)=84\left(x+13\right)\)
\(\Leftrightarrow49-21x+60x+24=84x+1092\)
\(\Leftrightarrow39x-84x=1092-73\)
=>-45x=1019
hay x=-1019/45
b: \(\Leftrightarrow21\left(x+3\right)-14=4\left(5x+9\right)-7\left(7x-9\right)\)
=>21x+63-14=20x+36-49x+63
=>21x+49=-29x+99
=>50x=50
hay x=1
c: \(\Leftrightarrow7\left(2x+1\right)-3\left(5x+2\right)=21x+63\)
=>14x+7-15x-6-21x-63=0
=>-22x-64=0
hay x=-32/11
d: \(\Leftrightarrow35\left(2x-3\right)-15\left(2x+3\right)=21\left(4x+3\right)-17\cdot105\)
=>70x-105-30x-45=84x+63-1785
=>40x-150-84x+1722=0
=>-44x+1572=0
hay x=393/11
a, msc 12.7=84
Chuyển vế về =0 rồi làm
b,msc 28
c,làm tương tự
a, \(\Rightarrow49-21x+60x+24=84x+1092\)
\(\Leftrightarrow-45x=1019\Leftrightarrow x=-\dfrac{1019}{45}\)
b, \(\Rightarrow21\left(x+3\right)-14=4\left(5x+9\right)-7\left(7x-9\right)\)
\(\Leftrightarrow21x+63-14=20x+36-49x+63\)
\(\Leftrightarrow50x=50\Leftrightarrow x=1\)
c, \(\Rightarrow14x+7-15x-6=21x+63\Leftrightarrow-22x=62\Leftrightarrow x=-\dfrac{31}{11}\)
d, \(\Rightarrow35\left(2x-3\right)-15\left(2x+3\right)=21\left(4x+3\right)-105.17\)
\(\Leftrightarrow70x-105-30x-45=84x+63-1785\)
\(\Leftrightarrow-44x=-1572\Leftrightarrow x=\dfrac{393}{11}\)
giải các phương trinh sau
1/ \(\dfrac{4x-4}{3}-\dfrac{7-x}{5}\)
2/ \(\dfrac{3x-9}{5}=\dfrac{3-x}{2}\)
3/ \(\dfrac{2x-1}{5}-\dfrac{3-x}{3}=1\)
4/ \(\dfrac{x-5}{3}+\dfrac{3x+4}{2}=\dfrac{5x+2}{6}\)
5/ \(\dfrac{x-3}{2}+\dfrac{2x+3}{5}=\dfrac{2x+5}{10}\)
\(1,\dfrac{4x-4}{3}=\dfrac{7-x}{5}\\ \Leftrightarrow5\left(4x-4\right)=3\left(7-x\right)\\ \Leftrightarrow20x-20=21-3x\\ \Leftrightarrow17x=41\Leftrightarrow x=\dfrac{41}{17}\)
\(2,\dfrac{3x-9}{5}=\dfrac{3-x}{2}\\ \Leftrightarrow6x-18=15-5x\\ \Leftrightarrow11x=33\\ \Leftrightarrow x=3\)
\(3,\dfrac{2x-1}{5}-\dfrac{3-x}{3}=1\\ \Leftrightarrow\dfrac{6x-3-15+5x}{15}=1\\ \Leftrightarrow11x-18=1\\ \Leftrightarrow x=\dfrac{19}{11}\)
\(4,\dfrac{x-5}{3}+\dfrac{3x+4}{2}=\dfrac{5x+2}{6}\\ \Leftrightarrow2x-10+9x+12=5x+2\\ \Leftrightarrow6x=0\Leftrightarrow x=0\)
\(5,\dfrac{x-3}{2}+\dfrac{2x+3}{5}=\dfrac{2x+5}{10}\\ \Leftrightarrow5x-15+4x+6=2x+5\\ \Leftrightarrow7x=14\\ \Leftrightarrow x=2\)
Tick nha
2: Ta có: \(\dfrac{3x-9}{5}=\dfrac{3-x}{2}\)
\(\Leftrightarrow6x-18=15-5x\)
\(\Leftrightarrow11x=33\)
hay x=3
Giải các phương trình và bất phương trình sau
a)\(\left|x-9\right|\) \(=2x+5\)
b) \(\dfrac{1-2x}{4}\) \(-2\) ≤ \(\dfrac{1-5x}{8}\) + x
c)\(\dfrac{2}{x-3}\)\(+\dfrac{3}{x+3}\)\(=\dfrac{3x+5}{x^2-9}\)
|x-9|=2x+5
Xét 3 TH
TH1: x>9 => x-9=2x+5 =>-9-5=x =>x=-14 (L)
TH2: x<9 => 9-x=2x+5 => 9-5=3x =>x=4/3(t/m)
TH3: x=9 =>0=23(L)
Vậy x= 4/3
Ta có:\(\dfrac{1-2x}{4}-2\le\dfrac{1-5x}{8}+x\\ \)
\(\dfrac{2-4x-16}{8}\le\dfrac{1-5x+8x}{8}\)
\(-4x-14\le1+3x\\ \Leftrightarrow7x+15\ge0\\ \Leftrightarrow x\ge-\dfrac{15}{7}\)
Ta có:
\(\dfrac{2}{x-3}+\dfrac{3}{x+3}=\dfrac{3x+5}{x^2-9}\)
\(\dfrac{2\left(x+3\right)+3\left(x-3\right)}{x^2-9}=\dfrac{3x+5}{x^2-9}\)
\(5x-4=3x+5\Leftrightarrow2x=9\Leftrightarrow x=\dfrac{9}{2}\)
1/ \(\dfrac{x-4}{3}+2x=\dfrac{4x-2}{6}\)
2/ \(\dfrac{5x-2}{5}-2=\dfrac{1-2x}{3}\)
3/ \(\dfrac{x-2}{2}-\dfrac{2}{3}=x-1\)
4/ \(\dfrac{2x-1}{3}+\dfrac{3x-2}{4}=\dfrac{4x-3}{5}\)
5/ \(\dfrac{x-3}{9}-\dfrac{x+2}{6}=\dfrac{x+4}{18}-\dfrac{1}{2}\)
1: Ta có: \(\dfrac{x-4}{3}+2x=\dfrac{4x-2}{6}\)
\(\Leftrightarrow2x-8+12x=4x-2\)
\(\Leftrightarrow10x=6\)
hay \(x=\dfrac{3}{5}\)
2: Ta có: \(\dfrac{5x-2}{5}-2=\dfrac{1-2x}{3}\)
\(\Leftrightarrow15x-6-30=10-20x\)
\(\Leftrightarrow35x=46\)
hay \(x=\dfrac{46}{35}\)
3: Ta có: \(\dfrac{x-2}{2}-\dfrac{2}{3}=x-1\)
\(\Leftrightarrow3x-6-4=6x-6\)
\(\Leftrightarrow-3x=4\)
hay \(x=-\dfrac{4}{3}\)
1)\(\dfrac{x-4}{3}+2x=\dfrac{4x-2}{6}\)
\(\Leftrightarrow\dfrac{\left(x-4\right).2}{3.2}+\dfrac{2x.6}{6}=\dfrac{4x-2}{6}\)
\(\Rightarrow2x-8+12x=4x-2\\ \Leftrightarrow10x=6\\ \Leftrightarrow x=\dfrac{3}{5}\)
4: Ta có: \(\dfrac{2x-1}{3}+\dfrac{3x-2}{4}=\dfrac{4x-3}{5}\)
\(\Leftrightarrow40x-20+45x-30=48x-36\)
\(\Leftrightarrow37x=14\)
hay \(x=\dfrac{14}{37}\)
5: Ta có: \(\dfrac{x-3}{9}-\dfrac{x+2}{6}=\dfrac{x+4}{18}-\dfrac{1}{2}\)
\(\Leftrightarrow2x-6-3x-6=x+4-9\)
\(\Leftrightarrow-x-x=-5-12=-17\)
hay \(x=\dfrac{17}{2}\)
GIẢI CÁC PT SAU:
\(\dfrac{2x+1}{3x+2}=5\)
\(\dfrac{2x^2-5x+2}{x-1}=\dfrac{2x^2+x+15}{x-3}\)
\(\dfrac{2x+3}{x-3}-\dfrac{4}{x+3}=\dfrac{24}{x^2-9}+2\)
Giải các phương trình sau:
a) 2,3 - 2(0,7 + 2) = 3,6 - 1,7x
b) \(\dfrac{5x+7}{4}-\dfrac{3x+5}{8}=\dfrac{4x+9}{5}-\dfrac{x-9}{3}\)
c) \(\dfrac{2x-1}{4}+\dfrac{x-3}{3}=\dfrac{4x-2}{3}-\dfrac{6x+7}{12}\)
d) (x - 1)(x + 2) - x(x + 3) = 8
a: =>3,6-1,7x=2,3-1,4-4=0,9-4=-3,1
=>1,7x=6,7
hay x=67/17
b: \(\Leftrightarrow30\left(5x+4\right)-15\left(3x+5\right)=24\left(4x+9\right)-40\left(x-9\right)\)
=>150x+120-45x-75=96x+216-40x+360
=>105x+45=56x+576
=>49x=531
hay x=531/49
a/ 5x+3 +5x=126
\(\dfrac{9-3x}{2}=\dfrac{5-2x}{3}\)
c/ 7-4(x+1)=5
a) \(5^{x+3}+5^x=126\)
\(\Rightarrow5^x\cdot\left(5^3+1\right)=126\)
\(\Rightarrow5^x\cdot\left(125+1\right)=126\)
\(\Rightarrow5^x=\dfrac{126}{126}\)
\(\Rightarrow5^x=1\)
\(\Rightarrow5^x=5^0\)
\(\Rightarrow x=0\)
b) \(\dfrac{9-3x}{2}=\dfrac{5-2x}{3}\)
\(\Rightarrow\dfrac{3\cdot\left(9-3x\right)}{6}=\dfrac{2\cdot\left(5-2x\right)}{6}\)
\(\Rightarrow3\cdot\left(9-3x\right)=2\cdot\left(5-2x\right)\)
\(\Rightarrow27-9x=10-4x\)
\(\Rightarrow-4x+9x=27-10\)
\(\Rightarrow5x=17\)
\(\Rightarrow x=\dfrac{17}{5}\)
c) \(7-4\left(x+1\right)=5\)
\(\Rightarrow4\left(x+1\right)=7-5\)
\(\Rightarrow4\left(x+1\right)=2\)
\(\Rightarrow x+1=\dfrac{1}{2}\)
\(\Rightarrow x=\dfrac{1}{2}-1\)
\(\Rightarrow x=-\dfrac{1}{2}\)
a. 3+5x=4.(3x-1)+5 b. 8-7.(x+2)=3.(x-1)-4
c\(\dfrac{8+5x}{3}=\dfrac{4-2x}{4}\) d.4x2+1=1 e. 9(x-1)2-1=0
Hãy chứng tỏ các phân thức sau bằng nhau
a/ \(\dfrac{x+3}{2x-5}=\dfrac{x^2+3x}{2x^2-5x}\)
b/ \(\dfrac{3-x}{x+3}=\dfrac{x^2-6x+9}{9-x^{ }}\)
c/ \(\dfrac{x^3+64}{\left(3-x\right)\left(x^2-4x+16\right)}\)\(=\dfrac{x-4}{x-3}\)
d/ \(\dfrac{x^3+6x^2-x-30}{x^3+3x^2-25x-75}=\dfrac{x-2}{x-5}\)
AI GIÚP MK VS Ạ AI NHANH MK SẼ VOTE Ạ
\(a,VP=\dfrac{x\left(x+3\right)}{x\left(2x-5\right)}=\dfrac{x+3}{2x-5}=VT\\ b,VP=\dfrac{\left(3-x\right)^2}{\left(3-x\right)\left(3+x\right)}=\dfrac{3-x}{x+3}=VT\\ c,VP=\dfrac{\left(x+4\right)\left(x^2-4x+16\right)}{\left(3-x\right)\left(x^2-4x+16\right)}=\dfrac{x+4}{3-x}=VP\left(bạn.sửa.lại.đề.đi\right)\\ d,VT=\dfrac{x^3-2x^2+8x^2-16x+15x-30}{x^3-5x^2+8x^2-40x+15x-75}\\ =\dfrac{\left(x-2\right)\left(x^2+8x+15\right)}{\left(x-5\right)\left(x^2+8x+15\right)}=\dfrac{x-2}{x-5}=VP\)