c là:
1-3=-2
d là:
1-4=-3
b là:
1-2=-1
a là:
1-(-1+-3+-2)=7
k cho mk nha
TL:
a+b+c+d = 1
=> b= 1- (a+c+d)= 1-2 =-1
=> c= 1 - (a+b+d) = 1- 3 = -2
=> d = 1- (a+b+c) = 1-4 =-3
=> a = 1 - ( -1) - (-2) - (-3) = 7
Học tốt
\(\hept{\begin{cases}a+b+c+d=1\\a+c+d=2\end{cases}}\Leftrightarrow b=-1\)
\(\hept{\begin{cases}a+b+c+d=1\\a+b+d=3\end{cases}}\Leftrightarrow c=-2\)
\(a+b+c=4\Leftrightarrow a=7\)
\(\Rightarrow d=-3\)
+/ c = ( a + b + c + d ) - ( a + b + d )
c = 1 - 3
c = - 2
+/ b = ( a + b + c + d ) - ( a + c + d )
b = 1 - 2
b = - 1
+/ d = ( a + b + c + d ) - ( a + b + c )
d = 1 - 4
d = - 3
+/ a = 1 - [ ( - 1 ) + ( - 2 ) + ( - 3 ) ]
a = 1 - ( - 6 )
a = 7
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