a: =>x+3=-20
hay x=-23
b: =>4x+12=0
hay x=-3
c: =>\(x-1\in\left\{1;-1;3;-3\right\}\)
hay \(x\in\left\{2;0;4;-2\right\}\)
a. x+3 =-20
=> x= -23
b. 4x+12=0 hoặc \(x^2+4=0\)
=> x=-3,\(x^2=-4\) ( vô lí)
=> x=-3
a, -120:(x+3) = 6
<=> x + 3 =-20 <=> x =-23
b, (4x+12)(x^2+4)=0
<=> x = -12/4 = -3
do x^2 + 4 > 0 Vậy x = -3
c, \(2x-5⋮x-1\Leftrightarrow2\left(x-1\right)-3⋮x-1\Rightarrow x-1\inƯ\left(-3\right)=\left\{\pm1;\pm3\right\}\)
x-1 | 1 | -1 | 3 | -3 |
x | 2 | 0 | 4 | -2 |