Y x 27 + Y x 42 + Y x 70 - Y x 19 = 16700
y x 27 + y x 42 -- y x 19 + y x 70 =16700
\(y.27+y.42-y.19+y.70=16700\)
\(\Leftrightarrow y\left(27+42-19+70\right)=16700\)
\(\Leftrightarrow y.120=16700\)
\(\Leftrightarrow y=\dfrac{835}{6}\)
Tìm x,y biết: \(\dfrac{x}{19}=\dfrac{y}{21}\)và 2x -y = 34.
A.x = 38; y = 42; B.x = -38; y = -42; C. x = 21; y = 19 D.x = -21; y = -1
`A)2/3=x/60`
`=>40/60=x/60`
`=>x=40`
`B)-1/2=y/18`
`=>-9/18=y/18`
`=>y=-9`
`C)3/x=y/35=-36/84`
Mà `-36/84=(-3 xx 12)/(7 xx 12)=-3/7`
`=>3/x=-3/7`
`=>x=-7`
`y/35=-3/7=-15/35`
`=>y=-15`
`D)7/x=y/27=-42/54`
Mà `-42/54=(-7 xx 6)/(9 xx 6)=-7/9`
`=>7/x=-7/9`
`=>x=-9`
`y/27=-7/9=-21/27`
`=>y=-21`
a) Ta có: \(\dfrac{2}{3}=\dfrac{x}{60}\)
\(\Leftrightarrow x=\dfrac{2\cdot60}{3}=40\)
Vậy: x=40
1,tim x
27:(x-3)
2tim y
42:y va 11<y<42
Tim x,y:
7/x=y/27=-42/54
Tìm số nguyên x,y biết
phần a.12/16=-x/4=21/y
phần b. 3/x=y/35=-42/70
a) 12/16 = -x/4 <=> 12.4=-x.16 <=> -16x=48 <=> x= -48/16=-3
12/16=21/y <=> 12.y=16.21 <=>12y=336 <=> y= 336:12 <=> y=28
b) 3/x =-42/70 <=> -42.x=70.3 <=> -42x=210 <=> x=210/(-42)=-5
y/35=-42/70 <=> 70.y=-42.35 <=>70y=-1470 <=> y= -1470: 70=-21
18 x y - 5 =4 27 : y +3 =6 126 :(42-y)=3 Y x2014/3 - y x 2013/3
A= x+7- (-12 )voi |x|=42
B= 27-x+y biết |x|=9 y=14
a) Ta có: \(\left|x\right|=42\Rightarrow x=\pm42\)
Nếu x = 42 => A = 42 + 7 + 12 = 61
Nếu x = -42 => A = -42 + 7 + 12 = -23
b) \(\left|x\right|=9\Rightarrow x=\pm9\)
Nếu x = 9 và y = 14 => B = 27 - 9 + 14 = 32
Nếu x = -9 và y = 14 => B = 27 + 9 + 14 = 50
Tìm các số nguyên x và y biết được là 7/x = y/27 = -42/54
\(\frac{7}{-9}=\frac{-21}{27}=\frac{-42}{54}\)
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