7,5x. 519=520.511
25%x + 7,5x = -21
25%x+7,5x=-21
1/4x+15/2x=-21
(1/4+15/2)x=-21
31/4x=-21
X= -21:31/4
X= -84/31
Vậy x=-84/31.
(7,5x(-3.5)-2.5x3,5)x1,9:(-17,5)
\(\left[7.5\cdot\left(-3.5\right)-2.5\cdot3.5\right]\cdot1.9:\left(-17.5\right)\)
\(=-3.5\cdot10\cdot\dfrac{1.9}{-17.5}\)
\(=\dfrac{35\cdot1.9}{17.5}=2\cdot1.9=3.8\)
(7,5x(-3.5)-2.5x3,5)x1,9:(-17,5)
Làm chi tiết nha
\(\dfrac{\left[7.5\cdot\left(-3.5\right)-2.5\cdot3.5\right]\cdot1.9}{-17.5}\)
\(=\dfrac{-3.5\left(7.5+2.5\right)\cdot1.9}{-17.5}\)
\(=\dfrac{35\cdot1.9}{17.5}=2\cdot1.9=3.8\)
7,5x X+X x 3,5=39,93
7,5x:(9-6+13/21)=2+13//25
7,5x X+X x 3,5=39,93
giup minh voi nha !
7,5*x+x*3,5=39,93
(7,5+3,5)*x=39,93
11x=39,93
x=39,93/11
x=3,63. Vậy x=3,63
519 + 519 = ?
Cách 1 :
Tổng là:
519 + 519 = 1038
Đáp số:1038
Cách 2 :
519 + 519
= 519 x 2
= 1038
Tìm x thuộc N, biết:
7,5x : (9- hỗn số 6 13/21)=7. (3/5)^2
\(7,5x:\left(9-6\dfrac{13}{21}\right)=7.\left(\dfrac{3}{5}\right)^2\\ 7,5x:\left(9-\dfrac{139}{21}\right)=7.\dfrac{9}{25}\\ 7,5x:\left(\dfrac{189}{21}-\dfrac{139}{21}\right)=\dfrac{63}{25}\\ 7,5x:\dfrac{50}{21}=\dfrac{63}{25}\\ 7,5x=\dfrac{63}{25}.\dfrac{50}{21}\\ 7,5x=\dfrac{3150}{525}\\ 7,5x=\dfrac{207}{35}\\ \dfrac{15}{2}x=\dfrac{207}{35}\\ x=\dfrac{207}{35}:\dfrac{15}{2}\\ x=\dfrac{207}{35}.\dfrac{2}{15}\\ x=\dfrac{414}{525}\\ x=\dfrac{138}{175}\)
Tìm x, biết : 7,5x : (9- hỗn số 6 13/21) = hỗn số 2 12/25
.tìm x:
\(7,5x:\left(9-6\frac{13}{21}\right)=2\frac{13}{25}\)
\(7,5x:\left(9-\frac{139}{21}\right)=\frac{63}{25}\)
\(7,5x:\left(\frac{189}{21}-\frac{139}{21}\right)=\frac{63}{25}\)
\(7,5x:\left(\frac{50}{21}\right)=\frac{63}{25}\)
\(7,5x=\frac{63}{25}.\frac{50}{21}\)
\(7,5x=6\)
\(x=6:7,5\)
\(x=\frac{4}{5}\)
vậy \(x=\frac{4}{5}\)
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