Giải:
a)-3/10-(-1/5)+x)=-3/2
-1/5+x =-3/10-(-3/2)
-1/5+x =6/5
x =6/5-(-1/5)
x =7/5
b)-(-x+3/4)-12/8.(-32/15)=-(-1/2)
x-3/4+16/5 =1/2
x-3/4 =1/2-16/5
x =-27/10
x =-27/10+3/4
x =-39/20
c)x-3/x+5=4/3
=>(x-3).3=4.(x+5)
3x-9 =4x+20
3x-4x =20+9
-1x =29
x =-29
Câu b cậu nên tính lại cho kĩ nhé, ấn máy tính dễ nhầm lắm đấy!
Mk phải ấn: -(39/20+3/4)-12/8.-32/15=1/2
Vì x là số âm mà đằng trước x là dấu ''-'' nên -(-39/20)=39/20 ; -(-1/2)=1/2
Chúc bạn học tốt!
tìm x :
a, x . \(\dfrac{-5}{8}\) = \(\dfrac{15}{32}\) b, \(\dfrac{3}{10}\) : x =\(\dfrac{-9}{20}\)
c, \(\dfrac{-1}{4}\) x + \(\dfrac{4}{5}\) =\(\dfrac{3}{4}\) d, \(\dfrac{-7}{8}\) + \(\dfrac{2}{3}\) :x = \(\dfrac{3}{5}\) . \(\dfrac{-5}{12}\)
tìm x biết
a)x-\(\dfrac{3}{7}\)=\(\dfrac{2}{5}.\dfrac{1}{4}\)
b)x+\(\dfrac{4}{5}\)=\(\dfrac{-5}{12}\).\(\dfrac{3}{25}\)
c)\(\dfrac{x}{182}\)=\(\dfrac{-6}{12}\).\(\dfrac{35}{91}\)
Bài 1:Tính hợp lí
a)-12,5+17,55-3,5+2,45
b)0,175-(\(2\dfrac{1}{3}\)+0,175)
c)\(\dfrac{5}{13}\).\(\dfrac{-3}{10}\)+\(\dfrac{3}{10}\).\(\dfrac{-8}{13}\)+(-0,7)
Bài 2:Tìm x biết
a)x+\(\dfrac{2}{5}\)=2,4
b)2x-\(\dfrac{4}{5}\)=-1,5
c)11-(15+11)=x-(25-9)
Bài 3:Cho A=\(\dfrac{1}{2^2}\)+\(\dfrac{1}{3^2}\)+\(\dfrac{1}{4^2}\)+\(\dfrac{1}{5^2}\)+....+\(\dfrac{1}{100^2}\)
Chứng tỏ A<1
Cho mk hỏi :
tìm x,biết
a,\(-3\dfrac{1}{2}\)x -0,75-1,25x=\(\left(\dfrac{-1}{2}\right)^2:\dfrac{-3}{4}+\dfrac{1}{6}\)
b, \(\dfrac{-2}{3}-\left(\dfrac{x}{2}-75\%\right)=\left(\dfrac{3}{-4}-\dfrac{9}{8}\right)^2:\dfrac{-3}{32}-1\dfrac{1}{3}\)
Tìm x biết:
\(a,\dfrac{4}{5}+x=\dfrac{2}{3}\)
\(b,\dfrac{-5}{6}-x=\dfrac{2}{3}\)
\(c,\dfrac{1}{2}x+\dfrac{3}{4}=\dfrac{-3}{10}\)
\(d,\dfrac{x}{3}-\dfrac{1}{2}=\dfrac{1}{5}\)
\(e,\dfrac{x+3}{15}=\dfrac{1}{3}\)
\(h,x+30\%x=-1,3\)
\(k,3\dfrac{1}{3}x+16\dfrac{1}{4}=13,25\)
\(m,\dfrac{x-6}{2}=\dfrac{50}{x-6}\)
\(n,x-13,4=24,5-6,7.5,2\)
\(p,15,7x+3,6x=-96,5\)
\(q,2,5x-11,6=-59,1\)
Tìm x, biết:
a) x+\(\dfrac{1}{6}\)=\(\dfrac{-3}{8}\) b) \(2-\left(\dfrac{3}{4}-x\right)=\dfrac{7}{12}\)
c) \(\dfrac{1}{2}x\)+\(\dfrac{1}{8}x=\dfrac{3}{4}\) d) 75%-\(1\dfrac{1}{2}+0,5:\dfrac{5}{12}-\left(\dfrac{-1}{2}\right)^2\)
Bài 9: Tìm \(x\) biết
1) \(\dfrac{9}{x}=\dfrac{-35}{105}\) 2) \(\dfrac{12}{5}=\dfrac{32}{x}\) 3) \(\dfrac{x}{2}=\dfrac{32}{x}\) 4) \(\dfrac{x-2}{4}=\dfrac{x-1}{5}\)
Bài 10: Cho biểu thức \(A=\dfrac{3}{n+2}\)
a) Số nguyên n phài thỏa mãn điều kiện gì để A là phân số? b) Tìm phân số A khi n = 0? n = 2? n = -7?
Tìm x biết
a, x+\(\dfrac{7}{12}\)=\(\dfrac{-5}{6}\) b, (\(\dfrac{2}{9}\)-x):\(\dfrac{5}{6}\)=\(\dfrac{-4}{3}\) c, \(\dfrac{-1}{2}\)=\(\dfrac{x-1}{6}\) d, \(\dfrac{4}{5}\):(\(\dfrac{3}{5}\)x-\(\dfrac{2}{3}\))=\(\dfrac{1}{5}\)
Tìm x biết: a) \(\dfrac{6}{-x}=\dfrac{x}{-24}\) b) \(x-\dfrac{7}{12}x+\dfrac{3}{8}x=\dfrac{5}{24}\)
c)\(\left(x-\dfrac{1}{3}\right)^2-\dfrac{1}{2}=1\dfrac{3}{4}\) d) \(\dfrac{x-3}{-2}=\dfrac{-8}{x-3}\)
e) \(\dfrac{9}{x}=\dfrac{-35}{105}\) f) \(\left(x-\dfrac{1}{2}\right)\left(-3-\dfrac{x}{2}\right)=0\)
