Tìm x
6)16/2*=2
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1. \(\text{6 + 2.(x - 19) = 16}.\)
\(\Leftrightarrow2.\left(x-19\right)=10.\)
\(\Leftrightarrow x-19=5.\)
\(\Leftrightarrow x=24.\)
Vậy \(x=24.\)
2. \(\text{(-240) : x – 16 = 64}.\)
\(\Leftrightarrow\left(-240\right):x=80.\)
\(\Leftrightarrow x=-3.\)
Vậy \(x=-3.\)
3. \(2x^3=16.\)
\(\Leftrightarrow x^3=8.\)
\(\Leftrightarrow x=2.\)
Vậy \(x=2.\)
\(\left|x^2+x+16\right|=x^2+\left|x+16\right|\)( vì \(x^2\ge0\))
\(\left|x^2+x-6\right|=x^2+\left|x-6\right|\)(vì \(x^2\ge0\))
\(\left|x+16\right|+\left|x-6\right|=\left|x+16\right|=\left|-x+6\right|\ge\left|22\right|=22\)
dấu = xảy ra khi và chỉ khi \(\left(x+16\right).\left(-x+6\right)\ge0\Rightarrow-16\le x\le6\)(1)
\(x^2\ge0\Rightarrow x^2+x^2\ge0\)
dấu = xảy ra khi và chỉ khi x=0 (2)
=> \(x^2+\left|x+16\right|+x^2+\left|x-6\right|\ge22+0=22\)
dấu = xảy ra khi dấu = ở (1) và (2) đồng thời xảy ra
=> x=0
Vậy min A=22 khi và chỉ khi x=0
p/s: ko chắc lắm, sai sót bỏ qua :))
a: ĐKXĐ: x∉{2;-2;3}
\(A=\left(\frac{4x}{x+2}-\frac{x^3-8}{x^3+8}\cdot\frac{4x^2-8x+16}{x^2-4}\right):\frac{16}{x^2-x-6}\)
\(=\left(\frac{4x}{x+2}-\frac{\left(x-2\right)\left(x^2+2x+4\right)}{\left(x+2\right)\left(x^2-2x+4\right)}\cdot\frac{4\left(x^2-2x+4\right)}{\left(x-2\right)\left(x+2\right)}\right):\frac{16}{\left(x-3\right)\left(x+2\right)}\)
\(=\left(\frac{4x}{x+2}-\frac{4\left(x^2+2x+4\right)}{\left(x+2\right)^2}\right)\cdot\frac{\left(x-3\right)\cdot\left(x+2\right)}{16}\)
\(=\frac{4x\left(x+2\right)-4\left(x^2+2x+4\right)}{\left(x+2\right)^2}\cdot\frac{\left(x-3\right)\left(x+2\right)}{16}=\frac{4x^2+8x-4x^2-8x-16}{\left(x+2\right)}\cdot\frac{x-3}{16}\)
\(=\frac{-16\left(x-3\right)}{16\left(x+2\right)}=\frac{-x+3}{x+2}\)
b: A<0
=>\(\frac{-x+3}{x+2}<0\)
=>\(\frac{x-3}{x+2}>0\)
=>x>3 hoặc x<-2
c: A>=5
=>\(\frac{-x+3}{x+2}-5\ge0\)
=>\(\frac{-x+3-5x-10}{x+2}\ge0\)
=>\(\frac{-6x-7}{x+2}\ge0\)
=>\(\frac{6x+7}{x+2}\le0\)
=>-2<x<=-7/6
42-2(x+16) +12 :2=6(x-1)+ (-4)^3 :16
42- 2x- 32 +6 = 6x - 6 - 64: 16
(42 - 32 +6) - 2x = 6x - 6 - 4
16 = 2x = 6x- 10
16+10= 2x+6x
26= 8x
x= 26/8
x= 13/4
16.(x-2) -6.(x-3)=6
=> 16x-32-6x+18=6
=>10x-14=6
=>10x=20
=>x=2
Vậy x=2
hok tốt
\(\left(x-4\right)\left(x^2+4x+16\right)-x\left(x^2-6\right)=2\)
\(\Rightarrow x^3-64-x^3+6x=2\)
\(\Rightarrow-64+6x=2\Rightarrow6x=66\Rightarrow x=11\)
\(\left(\dfrac{1}{16}\right)^{x+2}=\left(\dfrac{1}{32}\right)^6\)
\(\Leftrightarrow\dfrac{1}{16^{x+2}}=\dfrac{1}{32^6}\)
\(\Leftrightarrow\dfrac{1}{2^{4x+8}}=\dfrac{1}{2^{30}}\)
\(\Leftrightarrow4x+8=30\Leftrightarrow4x=22\Leftrightarrow x=\dfrac{11}{2}\)
b) (x – 4). (x2 + 4x + 16) – x. (x2 - 6) = 2
⇔ x3 + 4x2 + 16x – 4x2 – 16x – 64 – (x3 - 6x ) – 2= 0
⇔ x3 + 4x2 + 16x – 4x2 – 16x – 64 – x3 + 6x – 2= 0
⇔ 6x – 66 =0
⇔ 6x = 66
⇔ x = 66 : 6
⇔ x = 11
Vậy x = 11
a x * 4 + [1/2 + 1/4 + 1/8 + 1/6] = 23/16
x * 4 + 25/24 = 23/16
x * 4 = 23/16 - 25/24
x * 4 = 38/96 = 19/48
x = 19/48 / 4
x = 19/172
b x * 1 = 425
x = 425 / 1
x = 425
`16/2^x = 2`
`=>2^x=16/2`
`=>2^x=4`
`=>2^x=2^2`
`=>x=2`
Vậy x=2