Question

Determinați multimileA = { x€N | 7(4x - 3 )-4(3x-7)<71}
C= { x€Z | (x-1)^2 + 7 > ( x+ 4)^2 }

Answer 1

Sper ca se intelege. :)

Answer 2

$A.~~~7(4x-3)-4(3x-7)<71$
$28x-21-12x-28<71$
$16x+7<71$
$16x<71-4$
$16x<64$
$x<64:16$
$x<4$
$x\in{0 ; 1 ; 2 ; 3}$

$~~ \\ ~~$

$C.~~~(x-1)^{2}+7>(x+4)^{2}$
$x^{2}-2x+1+7>x^{2}+8x+16$
$-2x+1+7>8x+16$
$-2x+8>8x+16$
$-2x-8x>16-8$
$-10x>8$
$x<-\dfrac{8}{10}~~~simplifici~cu~2$
$x<-\dfrac{4}{5}$
$-4:5=-0,8$
$x\in{-0,7~;~-0,6~;~-0,5~;~\infty$