《2025年黄冈小状元同步计算天天练六年级数学下册北师大版》

解下面的比例。
(10 + x):2=(4.5 - x):0.6            (x + 15):(12x + 15)=1:9
x:(9 - 5 + x)=3:(9 - 5)              ($\frac 45$÷4):(x - 4)=(1÷4):x
(x - 4 - 3):(3 + 4)=x:(4 + 5)      (7x - 70):(4x + 50)=(3 + 5):5
(2x - 130):3=(x + 130):2          $\frac 49$:($\frac 23$+2x)=6:(18 + 9x)

答案：
(10 + x):2=(4.5 - x):0.6
解:2×(4.5 - x)=0.6×(10 + x)
9 - 2x = 6 + 0.6x
9 - 6 = 0.6x + 2x
3 = 2.6x
x = $\frac{3}{2.6}$
x = $\frac{15}{13}$
(x + 15):(12x + 15)=1:9
解:(x + 15)×9 = 12x + 15
9x + 15×9 = 12x + 15
15×9 - 15 = 12x - 9x
15×8 = 3x
x = $\frac{15×8}{3}$
x = 40
x:(9 - 5 + x)=3:(9 - 5)
解:(9 - 5)×x = 3×(9 - 5 + x)
4x = 12 + 3x
x = 12
($\frac{4}{5}$÷4):(x - 4)=(1÷4):x
解:($\frac{4}{5}$÷4)×x=(x - 4)×(1÷4)
$\frac{1}{5}$x = $\frac{1}{4}$x - 4×$\frac{1}{4}$
1 = ($\frac{1}{4}$ - $\frac{1}{5}$)x
x = 1÷$\frac{1}{20}$
x = 20
(x - 4 - 3):(3 + 4)=x:(4 + 5)
解:(x - 7)×9 = 7x
9x - 63 = 7x
9x - 7x = 63
2x = 63
x = 31.5
(7x - 70):(4x + 50)=(3 + 5):5
解:(7x - 70)×5=(4x + 50)×8
35x - 350 = 32x + 400
35x - 32x = 350 + 400
3x = 750
x = 250
(2x - 130):3=(x + 130):2
解:(2x - 130)×2=(x + 130)×3
4x - 260 = 3x + 390
4x - 3x = 390 + 260
x = 650
$\frac{4}{9}$:($\frac{2}{3}$ + 2x)=6:(18 + 9x)
解:$\frac{4}{9}$×(18 + 9x)=6×($\frac{2}{3}$ + 2x)
$\frac{4}{9}$×18 + $\frac{4}{9}$×9x = 6×$\frac{2}{3}$ + 6×2x
8 + 4x = 4 + 12x
8 - 4 = 12x - 4x
4 = 8x
x = $\frac{1}{2}$