c) ( 2x - 1)6 = 642
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\(2^x.2^{x+3}=64^2:2^5\)
\(2^x.2^x.2^3=2^{12}:2^5\)
\(2^x.\left(1+8\right)=2^7\)
\(2^x.9=2^7\)
\(\Rightarrow x=\varnothing\)
\(2^{2x+3}=64^2:2^5\)
\(\Leftrightarrow2^{2x+3}=2^7\)
hay x=2
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X : 6 + 12 948 = 15 642
X : 6 = 15 642 - 12 948
X : 6 = 2694
X = 2694 x 6
X = 16164
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x2 - 4y2 =1
<=>x-2y=1
hoặcx+2y=1
<=>x=1+2y
hoăcx=1-2y=>1+2y=1-2y
<=>4y = 0 <=> y=0=>x=1
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Bài 1:
a) \(8xy^2+24x^2y-32x^3y^2=8xy\left(y+3x-4x^2y\right)\)
b) \(x^2-16x-y^2+64=\left(x-8\right)^2-y^2=\left(x-8-y\right)\left(x-8+y\right)\)
Bài 2:
\(\left(x-4\right)^2-\left(12x+x^2\right)=6\)
\(\Rightarrow x^2-8x+16-12x-x^2=6\)
\(\Rightarrow20x=10\Rightarrow x=\dfrac{1}{2}\)
\(1,\\ =8xy\left(y+3x-4x^2y\right)\\ =\left(x-8\right)^2-y^2=\left(x-y-8\right)\left(x+y-8\right)\)
\(2,\Leftrightarrow x^2-8x+16-12x-x^2=6\\ \Leftrightarrow-20x=-10\\ \Leftrightarrow x=2\)
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a)
6 × 2 = 12 12 : 6 = 2 12 : 2 = 6 | 6 × 7 = 42 42 : 6 = 7 42 : 7 = 6 | 6 × 9 = 54 54 : 6 = 9 54 : 9 = 6 |
b)
24 g : 6 = 4 g
60 cm : 6 = 10 cm
36 l : 6 = 6 l
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135 x (20 + 3)
= 135 x 20 + 135 x 3
= 2700 + 405
= 3105.
427 x (10 + 8)
= 427 x 10 + 427 x 8
= 4270 + 3416
= 7686.
642 x (30 - 6)
= 642 x 30 - 642 x 6
= 19260 - 1452
= 18808.
287 x (40 - 8)
= 287 x 40 - 287 x 8
= 11480 - 2296
= 9184.
135x(20+3) 642 x (30-6)
= 135 x 20 + 135 x 3 = 642 x 30 - 642 x 6
= 2700+405 = 19 260 - 3852
= 3105 =15 408
427 x ( 10+8) 287 x (40 - 8)
= 427 x 10 + 427 x 8 = 287 x 40 - 287 x 8
= 4270 + 3416 =11 480 - 2296
=7686 = 9184
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five iphone 6 plus cost is : 642 x 5 = 3210 ( $ )
answer : 3210$
k for me
Bài giải
one iphones 6 plus run out of $ are :
642 / 2 = 321($)
five iphones 6plus out of the $ are:
321 x 5 = 1605($)
Answer: 1605$
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a) 190 + x = 2009
x = 2009 - 190
x = 1819
b) (x - 2) x 7 = 642
x- 2 = 642 : 7
x - 2 = \(\frac{642}{7}\)
x = \(\frac{642}{7}\) +2
x = \(\frac{656}{7}\)
c) x : 7 = 642
x = 642 x 7
x = 4494
a)190+x=2009
x=2009-190
x=1819. Vậy x=1819
b)(x-2)*7=642
x-2=642/7
x-2=91,7 .......
nói chung đề câu này sai
c)x:7=642
x=642*7
x=4494
\(\left(2x-1\right)^6=64^2\)
\(\Leftrightarrow\left(2x-1\right)^6=4^6\)
\(\Leftrightarrow\left[\begin{array}{nghiempt}2x-1=4\\2x-1=-4\end{array}\right.\)
\(\Leftrightarrow\left[\begin{array}{nghiempt}x=\frac{5}{2}\\x=-\frac{3}{2}\end{array}\right.\)
\(\left(2x-1\right)^6=64^2\)
\(\Rightarrow\left(2x-1\right)^6=4^6\)
\(\Rightarrow2x-1=\pm4\)
+) \(2x-1=4\Rightarrow x=\frac{5}{2}\)
+) \(2x-1=-4\Rightarrow x=\frac{-3}{2}\)
Vậy \(x=\frac{5}{2}\) hoặc \(x=\frac{-3}{2}\)