Question

f) 2*(3x+7)+19>3*(6x-1)
g) |4x+3| =5​

Answer 1

Răspuns:

f)

2*(3x+7)+19>3*(6x-1)

6x + 14 + 19 > 18x - 3

6x + 33 > 18x - 3

33 + 3 > 18x - 6x

36 > 12x

x < 36/12

x < 3

x ∈ (-∞; 3)

g)

|4x+3| =5​

4x + 3 = 5        4x + 3 = - 5

4x = 5 - 3         4x = - 5 - 3

4x = 2              4x = - 8

x = 2/5             x = - 8/4

x = 0,4             x = - 2

x = {-2; 0,4}

Answer 2

$\it f)\ 2(3x+7)+19 > 3(6x-1) \Rightarrow 6x+14+19 > 18x-3 \Rightarrow \\ \\ \Rightarrow 14+19+3 > 18x-6x \Rightarrow 36 > 12x|_{:12} \Rightarrow 3 > x \Rightarrow x < 3 \Rightarrow x\in(-\infty,\ 3)\\ \\ \\ g)\ |4x+3|=5 \Rightarrow 4x+3=\pm5 \Rightarrow 4x+3\in\{-5,\ 5\}|_{-3} \Rightarrow 4x\in\{-8,\ 2\}|_{:4} \Rightarrow \\ \\ \Rightarrow x\in\{-2;\ \ 0,5\}$