Question

Ex 11 via rog dau coroana

Answer 1

$a)3(1-2x)+8=32$

$3-6x+8=32$

$-6x=32-3-8$

$-6x=21 |:( - 3)$

$2x=-7$

$x = - \frac{7}{2} \: \notin \: \mathbb{N}$

$b)60 \div (3y + 2) = 12$

$60 \div 3y + 60 \div 2 = 12$

$\frac{20}{y} + 30 = 12$

$\frac{20}{y} = 12 - 30$

$\frac{20}{y} = - 18 \: | \div 2$

$y = - \frac{20}{18}$

$y = - \frac{10}{9} \: \notin \: \mathbb{N}$

$c)1 - 3(8x - 4) = 1$

$1 - 24x + 12 = 1$

$- 24x = 1 - 1 - 12$

$- 24x = - 12 \: | \div ( - 12)$

$2x = 1$

$x = \frac{1}{2} \: \notin \: \mathbb{N}$

$d)1605 + 4(3 - x) = 2011$

$1605 + 12 - 4x = 2011$

$- 4x = 2011 - 1605 - 12$

$- 4x = 394 \: | \div ( - 2)$

$2x = - 197 \: \notin \: \mathbb{N}$