Răspuns:
(a) [tex]\bf x\in( -\infty,-10)[/tex]
(c) [tex]\bf x\in (-\infty, -1)[/tex]
Explicație pas cu pas:
Salutare!
(a)
[tex]\bf 3\cdot(7x - 2)- 8\cdot(2x - 7) < 0[/tex]
[tex]\bf 21x - 6 - 16x +56 < 0[/tex]
[tex]\bf 21x - 16x +50 < 0[/tex]
[tex]\bf 5x +50 < 0[/tex]
[tex]\bf 5x < -50\:\:\:\Big|:5[/tex]
[tex]\bf x < -10 \implies\boxed{\bf x\in( -\infty,-10)}[/tex]
(c)
[tex]\bf 2\cdot(4x + 2) - 8\cdot(-4x + 1) <-14 - 15\cdot(-x+1)[/tex]
[tex]\bf 8x + 4 +32x -8 <-14 + 15x-15[/tex]
[tex]\bf 40x -4 <-29 + 15x[/tex]
[tex]\bf 40x -15x-4 <-29[/tex]
[tex]\bf 25x-4 <-29[/tex]
[tex]\bf 25x <-29 +4[/tex]
[tex]\bf 25x <-25\:\:\:\Big|:25\:\:\:\text{\it(impartim toata relatia cu 25)}[/tex]
[tex]\bf x <-1\implies \boxed{\bf x\in (-\infty, -1) }[/tex]
Regula de semnelor:
(+) · (+) = (+)
(+) · (-) = (-)
(-) · (-) = (+)
(-) · (+) = (-)
#copaceibrainly
