-11-|25-x|=(-8).2
3x^2- 53= -5
5.x^5+12=-148
3.(-2)^x -5 = -101
Ai giỏi toán giúp mk nha!!!
Làm hộ mk chi tiết nhé
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1) ĐKXĐ: \(16x^2-25\ge0\)
\(\Leftrightarrow x^2\ge\dfrac{25}{16}\)
\(\Leftrightarrow\left[{}\begin{matrix}x\ge\dfrac{5}{4}\\x\le-\dfrac{5}{4}\end{matrix}\right.\)
2) ĐKXĐ: \(4x^2-49\ge0\Leftrightarrow x^2\ge\dfrac{49}{4}\)
\(\Leftrightarrow\left[{}\begin{matrix}x\ge\dfrac{7}{2}\\x\le-\dfrac{7}{2}\end{matrix}\right.\)
3) ĐKXĐ: \(8-x^2\ge0\Leftrightarrow x^2\le8\)
\(\Leftrightarrow-2\sqrt{2}\le x\le2\sqrt{2}\)
4) ĐKXĐ: \(x^2-12\ge0\Leftrightarrow x^2\ge12\)
\(\Leftrightarrow\left[{}\begin{matrix}x\ge2\sqrt{3}\\x\le-2\sqrt{3}\end{matrix}\right.\)
5) ĐKXĐ: \(x^2+4\ge0\left(đúng\forall x\right)\)
a)12 x 18 + 14 x 3 - 255 : 17=25.58823529411765
b)68 + 42 x 5 - 625 : 25=5182
c) 13+ 21 x 5 - (198 : 11 - 8)=108
d) 1188 - 4 x (27 + 90 + 73 :10 )=
e) 5 + 8 + 11 + 14 +......+ 38 + 41=
f) 51 - 49 + 55 - 53 + 59 - 56 + 63 - 61 + 65=74
có mấy câu mình ko biết,xin lỗi bạn
mik chỉ ghi kết quả thôi nha
vì làm ra dài dòng lw
=> ta có:
x = 7
x = 4
x = 3
x = 4
x = 3
nha bn
5(x-7)=0
=>x-7=0
=>x=0+7
=>x=7
25(x-4)=0
=>x-4=0
=>x=0+4
=>x=4
34(2x-6)=0
=>2x-6=0
=>2x=0+6
=>2x=6
=>x=6:2
=>x=3
2016(3x-12)=0
=>3x-12=0
=>3x=0+12
=>3x=12
=>x=12:3
=>x=4
47(5x-15)=0
=>5x-15=0
=>5x=0+15
=>5x=15
=>x=15:5
=>x=3
a)√x−2+12√4x−8=√9x−18−2
=>√x−2+12√4(x−2)=√9(x−2)−2
=>√x−2+12√22(x−2)=√32(x−2)−2
=>√x−2+12.2√(x−2)=3√(x−2)−2
=>√x−2+24√(x−2)=3√(x−2)−2
=>√x−2+24√(x−2)-3√(x−2)=-2
=>√x−2(1+24-3)=-2
=>22√x−2=-2
=>√x−2=-2/22
=>√x−2=-1/11
=>x−2=1/121
=>x=1/121+2=243/121
b)√(3x−1)2=5
=>|3x−1|=5
=>3x−1=5 hoặc 3x−1=-5
=>3x=6 hoặc 3x=-4
=>x=2 hoặc x=-4/3
1)
\(=\sqrt{\left(\sqrt{11}\right)^2-2.\sqrt{11}.\sqrt{3}+\left(\sqrt{3}\right)^2}\)
\(=\sqrt{\left(\sqrt{11}-\sqrt{3}\right)^2}=\sqrt{11}-\sqrt{3}\)
2)
\(=\sqrt{\left(\sqrt{7}\right)^2-2.\sqrt{7}\sqrt{5}+\left(\sqrt{5}\right)^2}=\sqrt{\left(\sqrt{7}-\sqrt{5}\right)^2}=\sqrt{7}-\sqrt{5}\)
3)
\(=\sqrt{\left(\sqrt{11}\right)^2-2.\sqrt{11}\sqrt{5}+\left(\sqrt{5}\right)^2}=\sqrt{\left(\sqrt{11}-\sqrt{5}\right)}=\sqrt{11}-\sqrt{5}\)
4)
\(=\sqrt{3^2-2.3.\sqrt{5}+\left(\sqrt{5}\right)^2}=\sqrt{\left(3-\sqrt{5}\right)^2}=3-\sqrt{5}\)
5)
\(=\sqrt{3^2-2.3.2\sqrt{2}+\left(2\sqrt{2}\right)^2}=\sqrt{\left(3-2\sqrt{2}\right)^2}=3-2\sqrt{2}\)
\(\left(x+\frac{1}{2}\right)\left(x-\frac{3}{4}\right)=0\)
\(\Rightarrow\hept{\begin{cases}x+\frac{1}{2}=0\\x-\frac{3}{4}=0\end{cases}}\)
\(\Rightarrow\hept{\begin{cases}x=-\frac{1}{2}\\x=\frac{3}{4}\end{cases}}\)
+) -11-|25-x|=(-8).2
-11-|25-x|=-16
|25-x|=5
\(\Leftrightarrow\)\(\orbr{\begin{cases}25-x=5\\25-x=-5\end{cases}}\)\(\Leftrightarrow\)\(\orbr{\begin{cases}x=20\\x=30\end{cases}}\)
Vậy x \(\in\){20;30}
+) 3x2-53=-5
3x2=48
x2=16
x=\(\pm\)4
Vậy x=\(\pm\)4
+) 5x5+12=-148
5x5 = -160
x5= -32
x= -2
Vậy x= -2
+) 3.(-2)x -5 = -101
3.(-2)x = -96
(-2)x = -32
(-2)x= (-2)5
x=5
Vậy x=5
Chúc bạn học tốt
\(-11-\left|25-x\right|=\left(-8\right).2\)
\(\Rightarrow\left|25-x\right|=5\)
\(\Leftrightarrow\orbr{\begin{cases}25-x=5\\25-x=-5\end{cases}}\)
\(\Leftrightarrow\orbr{\begin{cases}x=20\\x=30\end{cases}}\)
\(3x^2-53=-5\)
\(\Rightarrow3x^2=48\)
\(\Rightarrow x^2=16\)
\(\Rightarrow x=\pm4\)
\(5x^5+12=-148\)
\(5x^5=-160\)
\(\Rightarrow x^5=-32\)
\(\Rightarrow x=-2\)
\(3\left(-2\right)^x-5=-101\)
\(\Rightarrow3.\left(-2\right)^x=-96\)
\(\Rightarrow\left(-2\right)^x=-32=\left(-2\right)^5\)
\(\Rightarrow x=5\)