( x+2)2 = 25
Những câu hỏi liên quan
\(\dfrac{-4+25}{x^2-25}-\dfrac{2x^2+x}{x^2-25}-\dfrac{2x}{5-x}\)
\(\dfrac{-4+25}{x^2-25}-\dfrac{2x^2+x}{x^2-25}-\dfrac{2x}{5-x}\)
= \(\dfrac{-4+25}{x^2-25}-\dfrac{2x^2+x}{x^2-25}+\dfrac{2x\left(x+5\right)}{x^2-25}\)
= \(\dfrac{-4+25-2x^2-x+2x^2+10x}{x^2-25}\)
= \(\dfrac{21+9x}{x^2-25}\)
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a) 25 - y^2 = 8(x+2009)^2 \Leftrightarrow 8(x+2009)^2 + y^2 = 25
Do y^2 \geq 0 \Rightarrow (x+2009)^2 \leq 25/8
\Rightarrow x+2009 =0 hoặc 1
Nếu x+2009 = 1 \Rightarrow 25 - y^2 = 1\Rightarrow y^2 = 26 (không tìm được y)
Nếu x+2009 = \Rightarrow 25 - y^2 = 0\Rightarrow y^2 = 25, y=5
Vậy (x=0;y=5)
25 . 15 + 75 . 45
-10 . 25 - 10 . 75 + 10 . 50
3^x-2 - 2^3 = 19
(2 x - 5)^3 = - 64
2(x-1)^2 + 3 = 35
125 - 25 (x + 3) = 50
2(x+ 3) - 1x = 4
a: =25(15+45*3)
=25*150
=3750
b: \(=-10\left(25+75-50\right)=-10\cdot50=-500\)
c: =>3^x-2=27
=>x-2=3
=>x=5
d: =>2x-5=-4
=>2x=1
=>x=1/2
e: =>2(x-1)^2=32
=>(x-1)^2=16
=>x-1=4 hoặc x-1=-4
=>x=-3 hoặc x=5
f: =>25(x+3)=75
=>x+3=3
=>x=0
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Cho phép tính sau: (25+7) : (56−25)× ( 8 : 3) :2+64 ×3%
Phép tính nào thực hiện được trong chương trình bảng tính?
A.
=(25+7)/(56-25)x(8/3)/2+6^4x3%
B.
=(25+7)/(56-2^5)x(8/3):2+6^4x3%
C.
=(25+7)/(56-25)*(8/3)/2+64* 3%
D.
=(25+7)/(56-2/5)x(8/3)/2+6^4x3%
(12/25)^x=(5/3)^-2-(-3/5)^4
(12/25)^x=144/625
(12/25)^x=(12/25)^2
=>x=2
\(\dfrac{-4x^2}{x^2-25}\)-\(\dfrac{2x^2+x}{x^2-25}\)-\(\dfrac{2x}{5-x}\)
Ta có: \(\dfrac{-4x^2}{x^2-25}-\dfrac{2x^2+x}{x^2-25}-\dfrac{2x}{5-x}\)
\(=\dfrac{-4x^2-2x^2-x}{\left(x-5\right)\left(x+5\right)}+\dfrac{2x}{x-5}\)
\(=\dfrac{-6x^2-x}{\left(x-5\right)\left(x+5\right)}+\dfrac{2x\left(x+5\right)}{\left(x-5\right)\left(x+5\right)}\)
\(=\dfrac{-6x^2-x+2x^2+10x}{\left(x-5\right)\left(x+5\right)}\)
\(=\dfrac{-4x^2+9x}{\left(x-5\right)\left(x+5\right)}\)
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2 tháng 3 2020 lúc 18:47
tìm x biết
\(\frac{\left(24-x\right)^2+\left(24-x\right)\left(x-25\right)+\left(x-25\right)^2}{\left(24-x\right)^2-\left(24-x\right)\left(x-25\right)+\left(x-25\right)^2}=\frac{19}{49}\)
Đặt \(a=24-x,b=x-25\)
Khi đó pt ban đầu trở thành :
\(\frac{a^2+ab+b^2}{a^2-ab+b^2}=\frac{19}{49}\)
\(\Leftrightarrow49\left(a^2+ab+b^2\right)=19\left(a^2-ab+b^2\right)\)
\(\Leftrightarrow30a^2+68ab+30b^2=0\)
\(\Leftrightarrow15a^2+34ab+15b^2=0\)
\(\Leftrightarrow\left(3a+5b\right)\left(5a+3b\right)=0\)
\(\Leftrightarrow\orbr{\begin{cases}3a=-5b\\5a=-3b\end{cases}}\)
Đến đây bạn thay vào là dễ rồi nhé ! Chúc bạn học tốt !
1/ (left(-dfrac{2}{3}right)^2 x dfrac{-9}{8} - 25% x dfrac{-16}{5} 2/ -1dfrac{2}{5} x 75% + dfrac{-7}{5} x 25% 3/ -2dfrac{3}{7} x (-125%) + dfrac{-17}{7} x 25% 4/ (-2)^3 x (dfrac{3}{4} x 0.25) : (2dfrac{1}{4} - 1dfrac{1}{6})
Đọc tiếp
1/ (\(\left(-\dfrac{2}{3}\right)\)\(^2\) x \(\dfrac{-9}{8}\) - 25% x \(\dfrac{-16}{5}\)
2/ -1\(\dfrac{2}{5}\) x 75% + \(\dfrac{-7}{5}\) x 25%
3/ -2\(\dfrac{3}{7}\) x (-125%) + \(\dfrac{-17}{7}\) x 25%
4/ (-2)\(^3\) x (\(\dfrac{3}{4}\) x 0.25) : (2\(\dfrac{1}{4}\) - 1\(\dfrac{1}{6}\))
1) Ta có: \(\left(-\dfrac{2}{3}\right)^2\cdot\dfrac{-9}{8}-25\%\cdot\dfrac{-16}{5}\)
\(=\dfrac{4}{9}\cdot\dfrac{-9}{8}-\dfrac{1}{4}\cdot\dfrac{-16}{5}\)
\(=\dfrac{-1}{2}+\dfrac{4}{5}\)
\(=\dfrac{-5}{10}+\dfrac{8}{10}=\dfrac{3}{10}\)
2) Ta có: \(-1\dfrac{2}{5}\cdot75\%+\dfrac{-7}{5}\cdot25\%\)
\(=\dfrac{-7}{5}\cdot\dfrac{3}{4}+\dfrac{-7}{5}\cdot\dfrac{1}{4}\)
\(=\dfrac{-7}{5}\left(\dfrac{3}{4}+\dfrac{1}{4}\right)=-\dfrac{7}{5}\)
3) Ta có: \(-2\dfrac{3}{7}\cdot\left(-125\%\right)+\dfrac{-17}{7}\cdot25\%\)
\(=\dfrac{-17}{7}\cdot\dfrac{-5}{4}+\dfrac{-17}{7}\cdot\dfrac{1}{4}\)
\(=\dfrac{-17}{7}\cdot\left(\dfrac{-5}{4}+\dfrac{1}{4}\right)\)
\(=\dfrac{17}{7}\)
4) Ta có: \(\left(-2\right)^3\cdot\left(\dfrac{3}{4}\cdot0.25\right):\left(2\dfrac{1}{4}-1\dfrac{1}{6}\right)\)
\(=\left(-8\right)\cdot\left(\dfrac{3}{4}\cdot\dfrac{1}{4}\right):\left(\dfrac{9}{4}-\dfrac{7}{6}\right)\)
\(=\left(-8\right)\cdot\dfrac{3}{16}:\dfrac{54-28}{24}\)
\(=\dfrac{-3}{2}\cdot\dfrac{24}{26}\)
\(=\dfrac{-72}{52}=\dfrac{-18}{13}\)
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20 tháng 12 2021 lúc 20:26
Phân tích đa thức \(x^2\) + 2xy + \(y^2\)- 25 thành nhân tử. Kết quả là:
A. (x + y - 5)(x – y + 5). B. (x + y - 5)(x + y + 5).
C. (x + y - 25)(x – y + 25). D. (x + y - 25)(x + y + 25).
(x+9)×(x^2-25)=0
(x-7).(16+x^2).(25-x^2)=0
\((x+9)(x^2-25)=0\)
\(\Rightarrow\orbr{\begin{cases}x+9=0\\x^2-25=0\end{cases}\Rightarrow\orbr{\begin{cases}x=-9\\x\in\left\{-5;5\right\}\end{cases}}}\)
\((x-7)(16+x^2)(25-x^2)=0\)
\(\Rightarrow\hept{\begin{cases}x-7=0\\16+x^2=0\\25-x^2=0\end{cases}\Rightarrow\hept{\begin{cases}x=7\left(TM\right)\\x^2=-16\left(KTM\right)\\x\in\left\{-5;5\right\}\end{cases}}}\)
Học tốt!