47 x m + m x 55 - m x 2
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\(\dfrac{59-x}{41}+\dfrac{57-x}{43}+\dfrac{55-x}{45}+\dfrac{53-x}{47}+\dfrac{51-x}{49}=-5\)
\(\Leftrightarrow\dfrac{59-x}{41}+1+\dfrac{57-x}{43}+1+\dfrac{55-x}{45}+1+\dfrac{53-x}{47}+1+\dfrac{51-x}{49}+1=0\)
\(\Leftrightarrow\dfrac{100-x}{41}+\dfrac{100-x}{43}+\dfrac{100-x}{45}+\dfrac{100-x}{47}+\dfrac{100-x}{49}=0\)
\(\Leftrightarrow\left(100-x\right)\left(\dfrac{1}{41}+\dfrac{1}{43}+\dfrac{1}{45}+\dfrac{1}{47}+\dfrac{1}{49}\right)=0\)
Mà \(\dfrac{1}{41}+\dfrac{1}{43}+\dfrac{1}{45}+\dfrac{1}{47}+\dfrac{1}{49}\ne0\)
\(\Leftrightarrow100-x=0\Leftrightarrow x=100\)
Vậy x = 100
1) Ta có:
\(\left(3x+5\right)\left(11+3m\right)-7\left(x+2\right)=115\) có nghiệm x=1
Thay x = 1 vào pt ta được:
\(\left(3.1+5\right)\left(11+3m\right)-7\left(1+2\right)=115\)
\(\Leftrightarrow8\left(11+3m\right)-7.3=115\)
\(\Leftrightarrow88+24m-21=115\)
\(\Leftrightarrow88+24m=136\)
\(\Leftrightarrow24m=48\)
\(\Leftrightarrow m=2\)
Vậy để pt nhận x=1 làm nghiệm thì m = 2
2) Ta có:
\(2\left(x+n\right)\left(x+2\right)-3\left(x-1\right)\left(x^2+1\right)=15\) có nghiệm x = -1
Thay x = -1 vào pt ta được:
\(2\left(-1+n\right)\left(-1+2\right)-3\left(-1-1\right)\left[\left(-1\right)^2+1\right]=15\)
\(\Leftrightarrow\left(-2+2n\right).1+6.2=15\)
\(\Leftrightarrow-2+2n+12=15\)
\(\Leftrightarrow2n+10=15\)
\(\Leftrightarrow n=2,5\)
(Lần sau, "bé" nhớ sử dụng công cụ công thức trực quan nhé, dịch của "bé" mình mệt ghê :V)
a,
\(\frac{x+1}{55}+\frac{x+3}{53}+\frac{x+5}{51}=\frac{x+7}{49}+\frac{x+9}{47}+\frac{x+11}{45}\\ \Leftrightarrow\frac{x+1}{55}+1+\frac{x+3}{53}+1+\frac{x+5}{51}+1=\frac{x+7}{49}+1+\frac{x+9}{47}+1+\frac{x+11}{45}+1\\ \Leftrightarrow\frac{x+56}{55}+\frac{x+56}{53}+\frac{x+56}{51}=\frac{x+56}{49}+\frac{x+56}{47}+\frac{x+56}{45}\\ \Leftrightarrow\left(x+56\right)\left(\frac{1}{55}+\frac{1}{53}+\frac{1}{51}-\frac{1}{49}-\frac{1}{47}-\frac{1}{45}\right)=0\)
And... u know dat right? ( ͡~ ͜ʖ ͡°)
b,
\(\frac{x+29}{31}-\frac{x+27}{33}=\frac{x+17}{43}-\frac{x+15}{45}\\ \Leftrightarrow\frac{x+29}{31}+1-\frac{x+27}{33}+1=\frac{x+17}{43}+1-\frac{x+15}{45}+1\\ \Leftrightarrow\frac{x+60}{31}-\frac{x+60}{33}=\frac{x+60}{43}-\frac{x+60}{45}\\ \Leftrightarrow\left(x+60\right)\left(\frac{1}{31}-\frac{1}{33}-\frac{1}{43}+\frac{1}{45}\right)=0\)
Ok, phần còn lại là của bạn nhé. :)
Chúc bạn học tốt nha.
a, \(\dfrac{x-45}{55}-1+\dfrac{x-47}{53}-1=\dfrac{x-55}{45}-1+\dfrac{x-53}{47}-1\)
\(\Leftrightarrow\dfrac{x-100}{55}+\dfrac{x-100}{53}=\dfrac{x-100}{45}+\dfrac{x-100}{47}\)
\(\Leftrightarrow\left(x-100\right)\left(\dfrac{1}{55}+\dfrac{1}{53}-\dfrac{1}{45}-\dfrac{1}{47}\ne0\right)=0\Leftrightarrow x=100\)
b, \(\dfrac{x+1}{2004}+1+\dfrac{x+2}{2003}+1=\dfrac{x+3}{2002}+1+\dfrac{x+4}{2001}+1\)
\(\Leftrightarrow\dfrac{x+2005}{2004}+\dfrac{x+2005}{2003}=\dfrac{x+2005}{2002}+\dfrac{x+2005}{2001}\)
\(\Leftrightarrow\left(x+2005\right)\left(\dfrac{1}{2004}+\dfrac{1}{2003}-\dfrac{1}{2002}-\dfrac{1}{2001}\ne0\right)=0\Leftrightarrow x=-2005\)
a. lấy mỗi phân số e cộng vs 2 là bt làm ra liền
b, - 1 hoặc + 1 vs mỗi phân số nha
\(\dfrac{x-45}{55}+\dfrac{x-47}{53}=\dfrac{x-55}{45}+\dfrac{x-53}{47}\)
\(\Leftrightarrow\left(\dfrac{x-45}{55}-1\right)+\left(\dfrac{x-47}{53}-1\right)=\left(\dfrac{x-55}{45}-1\right)+\left(\dfrac{x-53}{47}-1\right)\)
\(\Leftrightarrow\dfrac{x-100}{55}+\dfrac{x-100}{53}=\dfrac{x-100}{45}+\dfrac{x-100}{47}\)
\(\Leftrightarrow\dfrac{x-100}{55}+\dfrac{x-100}{53}-\dfrac{x-100}{45}-\dfrac{x-100}{47}=0\)
\(\Leftrightarrow\left(x-100\right)\left(\dfrac{1}{55}+\dfrac{1}{53}-\dfrac{1}{45}-\dfrac{1}{47}\right)=0\)
Do \(\dfrac{1}{55}+\dfrac{1}{53}-\dfrac{1}{45}-\dfrac{1}{47}\ne0\) nên x - 100 = 0 <=> x = 100
m x 95 - m x 35 - m x 55 =225
m x (95-35-55)=225
m x 5=225
m=225:5
m=45
Đáp số: m=45
tk mình nha
\(\Rightarrow\)M\(\times\)/95-35-55/=225\(\Rightarrow\)m=225\(\div\)5=45
Ta có: \(M=55+225+375+13+x\)
\(=x+668\)
a: Để \(M⋮5\) thì \(x=5k+2\)
b: Để M chia 5 dư 4 thì \(x=5k+1\)
c: Để M chia 5 dư 3 thì x=5k
Trả lời :
47 x m + m x 55 - m x 2
= m x (47 + 55 - 2)
= m x 100
= 100m
~Study well~
#KSJ
= 100m
k mình nha!