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Lời giải:
$5(a+b)=7(a+b)$
$\Rightarrow 7(a+b)-5(a+b)=0$
$\Rightarrow 2(a+b)=0$
$\Rightarrow a+b=0$
$\Rightarrow a=-b$
Thương của $a$ và $b$: $a:b=(-b):b=-1$
ta có: 3a+3b=5a-5b
3a+5a=3b-5b
8a=-4b
8:-4=a/b
=> a/b = -2
hên sui hà
3(a+b)=5(a-b)
3a + 3b = 5a - 5b
3a + 3b + 5b = 5a
3b + 5b = 5a - 3a
8b = 2a
4b = a (1)
Từ (1) ta có:
a : b = 4
=> thương của a và b bằng 4
ta có 3( a+b)= 5(a-b) <=> 3a + 3b = 5a - 5b <=> 8b = 2a
Ap dụng ính chất của tỉ lệ thức ta có a/ b = 8/2 => a/b = 4
\(3\left(a+b\right)=5\left(a-b\right)\)
\(\Leftrightarrow3a+3b=5a-5b\)
\(\Leftrightarrow5a-3a=5b+3b\)
\(\Leftrightarrow2a=8b\)
\(\Leftrightarrow a=4b\)
\(\Leftrightarrow\frac{a}{b}=4\)
Vậy \(\frac{a}{b}=4\)
\(3\left(a+b\right)=5\left(a-b\right)\)
\(\Rightarrow3a+3b=5a-5b\)
\(\Rightarrow3b+5b=5a-3a\)
\(\Rightarrow8b=2a\)
\(\Rightarrow\frac{a}{b}=\frac{8}{2}=4\)
a) goi hai so la a ; b va a >b
vi UCLN(a,b)=18=>a=18k ; b=18q (trong do UCLN (k,q)=1 va k>q)
=>a+b=162
18k+18q =162
18(k+q)=162
k+q=9
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52542000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000 | 542454550212.100000000000000000000000000000000000000000000000000000000000000000000000000000 |
Đặt (a;b) = d thì a = dm ; b = dn (m,n \(\in\) N*)
Ta có : a + b = dm + dn = d(m + n) = 92 (1)
và [a;b] = [dm;dn] = dmn
=> (a;b) + [a;b] = d + dmn = d(1 + mn) = 484 (2)
Từ (1) và (2) => ......
Vì 3 (a + b) = 5 (a - b) nên 3 (a + b) và 5 (a - b) là bội chung của 3 và 5.
=> Giá trị nhỏ nhất của 2 tích 3 (a + b) và 5 (a - b) sẽ là 15.
3 (a + b) = 15
=> a + b = 15 : 3
=> a + b = 5 (1)
5 (a - b) = 15
=> a - b = 15 : 5
=> a - b = 3 (2)
Từ (1) và (2) => a = 4 và b = 1