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a; -2\(x\) - 3.(\(x-17\)) = 34 - 2.( - \(x\) + 25)
- 2\(x\) - 3\(x\) + 51 = 34 + 2\(x\) - 50
2\(x\) + 2\(x\) + 3\(x\) = - 34 + 50 + 51
7\(x\) = 67
\(x\) = 67 : 7
\(x\) = \(\dfrac{67}{7}\)
Vậy \(x\) = \(\dfrac{67}{7}\)
b; 17\(x\) + 3.(- 16\(x\) - 37) = 2\(x\) + 43 - 4\(x\)
17\(x\) - 48\(x\) - 111 = 2\(x\) - 4\(x\) + 43
- 31\(x\) - 2\(x\) + 4\(x\) = 111 + 43
- \(x\) x (31 + 2 - 4) = 154
- \(x\) x (33 - 4) = 154
- \(x\) x 29 = 154
- \(x\) = 154 : (-29)
\(x\) = - \(\dfrac{154}{29}\)
Vậy \(x=-\dfrac{154}{29}\)
a) \(\text{2(x-51)=2.2^2+20}\)
\(2\left(x-51\right)=2.4+20\)
\(2\left(x-51\right)=28\)
\(x-51=28\div2\)
\(x-51=14\)
\(x=14+51\)
\(\text{b)3.(x+1)-26=541}\)
\(3.\left(x+1\right)=541+26\)
\(3\cdot\left(x+1\right)=567\)
\(x+1=567\div3\)
\(x+1=189\)
\(x=189-1\)
\(x=188\)
\(x=65\)
\(\text{c)4(x-3)=7^2-1^10}\)
\(4\left(x-3\right)=49-1\)
\(4\left(x-3\right)=48\)
\(x-3=48\div4\)
\(x-3=12\)
\(x=12+3\)
\(x=15\)
\(\text{e)2x-138=2^3.3^2}\)
\(2x-138=8\cdot9\)
\(2x-138=72\)
\(2x=72+138\)
\(2x=210\)
\(x=210\div2\)
\(x=105\)
\(\text{f)(x-1)^4=16}\)
\(\left(x-1\right)^4=2^4\)
\(x-1=2\)
\(x=2+1\)
\(x=3\)
a/ -3x=-60+30
=> -3x=-30
=> x=(-30):(-3)
=> x=10
Ban oi phai x,y∈Z thi moi lam dc
b/x.y=7
Vi x,y∈U(7)=(1,-1,7,-7)
Với x=1 => y=7 y=1=>x=7
x=-1 =>x=-7 y=-1=>x=-7
x=7 => x=1 y=7=>x=7
x=-7 => x=-1 y=-7=>x=-1
c/(x-1)(y+2)=-7
x-1 va y+2∈U(-7)=(1,-1,7,-7)
Bạn giải giống câu b/ nhưng x,y trái đâu nhé
d/2x-3=5x-7
=>(-3)+7=5x-2x
=>4=3x
=>x=4/3
e/(-2)2-8x=20
=>4-8x=20
=>4-20=8x
=>-16=8x
=>x=-2
f/17-(-31)+3x=2x-(-50)
=>17+31+3x=2x+50
=>49+3x=2x+50
=> 3x-2x=50-49
=> x=1
g/2y2-16=34
=>2y2=34+16
=>2y2=50
=>y2=50:2
=>y2=25=52=(-5)2
=>y=5 va y=-5
a) \(\left(-3\right)x-30=-60\)
\(\Leftrightarrow\left(-3\right)x=-60+30\)
\(\Leftrightarrow\left(-3\right)x=-30\)
\(\Leftrightarrow x=\left(-30\right):\left(-3\right)\)
\(\Leftrightarrow x=10\)
b) \(xy=7\)
\(\Rightarrow xy=1.7=7.1=\left(-1\right).\left(-7\right)=\left(-7\right).\left(-1\right)\)
Ta có bảng sau:
KL: Các cặp số (x; y)...
c) \(\left(x-1\right)\left(y+2\right)=-5\)
\(\Rightarrow\left(x-1\right)\left(y+2\right)=1.\left(-5\right)=\left(-5\right).1=\left(-1\right).5=5.\left(-1\right)\)
Ta có bảng sau:
KL: Các cặp số (x; y)...
d) \(2x-3=5x-7\)
\(\Leftrightarrow2x-5x=-7+3\)
\(\Leftrightarrow-3x=-4\)
\(\Leftrightarrow x=\dfrac{4}{3}\)
e) \(\left(-2\right)^2-8x=20\)
\(\Leftrightarrow4-8x=20\)
\(\Leftrightarrow8x=4-20\)
\(\Leftrightarrow8x=-16\)
\(\Leftrightarrow x=-2\)
f) \(17-\left(-31\right)+3x=2x-\left(-50\right)\)
\(\Leftrightarrow17+31+3x=2x+50\)
\(\Leftrightarrow48+3x=2x+50\)
\(\Leftrightarrow3x-2x=50-48\)
\(\Leftrightarrow x=2\)
g) \(2y^2-16=34\)
\(\Leftrightarrow2y^2=34+16\)
\(\Leftrightarrow2y^2=50\)
\(\Leftrightarrow y^2=50:2=25\)
\(\Leftrightarrow y^2=5^2=\left(-5\right)^2\)
\(\Leftrightarrow\left[{}\begin{matrix}y=5\\y=-5\end{matrix}\right.\)