Tìm x biết
(2,8x - 32) : \(\frac{2}{3}\)= -90
(4,5 - 2x) . \(1\frac{4}{7}\)= \(\frac{11}{14}\)
b) Tìm x, biết:
(2,8x - 32): \(\frac{2}{3}\)= -90; (4,5 - 2x) . \(1\frac{4}{7}\)= \(\frac{11}{14}\).
Tìm x, biết:
a) (2,8x-32):\(\frac{2}{3}\)= -90
b) (4,5-2x).1\(\frac{4}{7}\)= \(\frac{11}{14}\)
\(a.\left(2,8x-32\right):\frac{2}{3}=-90\)
\(2,8x-32=-90\cdot\frac{2}{3}=-30\cdot\frac{2}{1}\)
\(2,8x-32=-60\)
\(2,8x=-60+32\)
\(2,8x=28\)
\(x=\frac{28}{2,8}=10\). Vậy x=10
\(b.\left(4,5-2x\right)\cdot1\frac{4}{7}=\frac{11}{14}\)
\(4,5-2x=\frac{11}{14}:\frac{11}{7}=\frac{11}{14}\cdot\frac{7}{11}\)
\(4,5-2x=\frac{1}{2}\)
\(2x=\frac{45}{10}-\frac{1}{2}=\frac{9}{2}-\frac{1}{2}=\frac{8}{2}\)
\(2x=4\)
\(x=\frac{4}{2}=2\) . Vậy x=2
Chúc bạn học tốt!^_^
a)(2,8x-32):\(\frac{2}{3}\)=-90
(2,8x-32) =(-90).\(\frac{2}{3}\)
(2,8x-32) =(-60)
2,8x =(-60)+32
2,8x =(-28)
x =(-28):2,8
x =(-10)
b)(4,5-2x).1\(\frac{4}{7}\)=\(\frac{11}{14}\)
(4,5-2x).\(\frac{11}{7}\)=\(\frac{11}{14}\)
(4,5-2x) =\(\frac{11}{14}\):\(\frac{11}{7}\)
(4,5-2x) =\(\frac{1}{2}\)
2x =4,5-\(\frac{1}{2}\)
2x =4
x =4:2
x =2
Tìm x, biết :
\(\left(2,8x-32\right)\div\frac{2}{3}=-90\)
\(\left(4,5-2x\right)\times1\frac{4}{7}=\frac{11}{14}\)
\(\left(2,8x-32\right)\div\frac{2}{3}=-90\)
\(\Rightarrow2,8x-32=-60\)
\(\Rightarrow2,8x=-28\)
\(\Rightarrow x=-10\)
\(\left(4,5-2x\right)\times1\frac{4}{7}=\frac{11}{14}\)
\(\Rightarrow4,5-2x=\frac{1}{2}\)
\(\Rightarrow2x=4\)
\(\Rightarrow x=2\)
Tìm x, biết:
a) (2,8x - 32) : 2/3 = -90
b) (4,5 - 2x) . 1 4/7(hỗn số) = 11/14
Tìm x:
a) (2,8x - 32) :\(\frac{2}{3}\)=90
b) 4,5 - 2x . \(1\frac{4}{7}\)=\(\frac{11}{14}\)
c) (x+ \(\frac{1}{4}-\frac{1}{3}\) ): (2+\(\frac{1}{6}-\frac{1}{4}\))=\(\frac{7}{46}\)
d)\(\frac{13}{15}-\left(\frac{13}{21}+x\right).\frac{7}{12}=\frac{7}{10}\)
\(\left(2.8x-32\right):\frac{2}{3}=90\)
\(2.8\cdot x-32=90\cdot\frac{2}{3}\)
\(\frac{14}{5}x-32=60\)
\(\frac{14}{5}x=60+32\)
\(\frac{14}{5}x=92\)
\(x=\frac{230}{7}\)
B , c , d tương tự
Tim x :
a) ( 2,8x - 32 ) :\(\frac{2}{3}\) = -90
b) ( 4,5 - 2x ) . 1\(\frac{4}{7}\) =\(\frac{11}{14}\)
a)(2,8x-32):\(\frac{2}{3}\)=-90
2,8x-32=-90.\(\frac{2}{3}\)
2,8x =-60+32
x =-28:2,8
x=-10
b)(4,5-2x).1\(\frac{4}{7}\)=\(\frac{11}{14}\)
4,5-2x =\(\frac{11}{14}:\frac{11}{7}\)
-2x =\(\frac{1}{2}\)
x=-1/4
( 2,8x -32 ) : \(\frac{2}{3}\) = -90 ( 4,5 - 2x ) . 1\(\frac{4}{7}\) = \(\frac{11}{14}\)
\(\left(2,8x-32\right):\frac{2}{3}=-90\)
\(2,8x-32=-60\)
\(2,8x=-28\)
\(x=-10\)
Vậy x = -10
\(\left(4,5-2x\right).1\frac{4}{7}=\frac{11}{14}\)
\(\left(4,5-2x\right).\frac{11}{7}=\frac{11}{14}\)
\(4,5-2x=\frac{1}{2}\)
\(2x=4\)
\(x=2\)
Vây x = 2
1. Tính giá trị biểu thức:
\(A=-1,6:\left(1+\frac{2}{3}\right)\)
\(B=1,4.\frac{15}{49}-\left(\frac{4}{5}+\frac{2}{3}\right):2\frac{1}{5}\)
2. Tìm x:
a, \(\left(2,8x-32\right):\frac{2}{3}=-90\)
b, \(\left(4,5-2x\right).1\frac{4}{7}=\frac{11}{14}\)
Tìm \(x\), biết :
a) \(\left(2,8x-32\right):\dfrac{2}{3}=-90\)
b) \(\left(4,5-2x\right):1\dfrac{4}{7}=\dfrac{11}{14}\)
a, \(\left(2,8x-32\right):\dfrac{2}{3}=-90\)
\(\Rightarrow2,8x-32=-60\)
\(\Rightarrow2,8x=-28\)
\(\Rightarrow x=-10\)
Vậy x = -10
b, \(\left(4,5-2x\right):1\dfrac{4}{7}=\dfrac{11}{14}\)
\(\Rightarrow\left(4,5-2x\right):\dfrac{11}{7}=\dfrac{11}{14}\)
\(\Rightarrow4,5-2x=\dfrac{121}{98}\)
\(\Rightarrow2x=\dfrac{160}{49}\)
\(\Rightarrow x=\dfrac{80}{49}\)
Vậy \(x=\dfrac{80}{49}\)
\(a,\left(2,8x-32\right):\dfrac{2}{3}=-90\)
\(2,8x-32=-90.\dfrac{2}{3}\)
\(2,8x-32=-60\)
\(2,8x=-60+32\)
\(2,8x=-28\)
\(x=-28:2,8\)
\(x=-10\)
Vậy \(x=-10\)
\(b,\left(4,5-2x\right):1\dfrac{4}{7}=\dfrac{11}{14}\)
\(\left(4,5-2x\right):\dfrac{11}{7}=\dfrac{11}{14}\)
\(4,5-2x=\dfrac{11}{14}.\dfrac{11}{7}\)
\(4,5-2x=\dfrac{121}{98}\)
\(2x=4,5-\dfrac{121}{98}\)
\(2x=\dfrac{160}{49}\)
\(x=\dfrac{160}{49}:2\)
\(x=\dfrac{80}{49}\)
Vậy \(x=\dfrac{80}{49}\)
\(a,\left(2,8x-32\right):\dfrac{2}{3}=-90\)
\(2,8x-32\) \(=-90.\dfrac{2}{3}\)
\(2,8x-32\)