Question

Resuelve y comprueba las siguientes ecuaciones:

1. 3x + 5 = 20
2. 2x - 1 = 89
3. 9x + 3 = 38​

Answer 1

Explicación paso a paso:

$1. \: 3x + 5 = 20 \\ 3x = 20 - 5 \\ 3x = 15 \\ \frac{3x}{3} = \frac{15}{3} \\ x = 5$

Comprobación 1:

$3(5) + 5 = 20 \\ 15 + 5 = 20 \\ 20 = 20$

$2. \: 2x - 1 = 89 \\ 2x = 89 + 1 \\ 2x = 90 \\ \frac{2x}{2} = \frac{90}{2} \\ x = 45$

Comprobación 2:

$2(45) - 1 = 89 \\ 90 - 1 = 89 \\ 89 = 89$

$3. \: 9x + 3 = 38 \\ 9x = 38 - 3 \\ 9x = 35 \\ \frac{9x}{9} = \frac{35}{9} \\ x = \frac{35}{9}$

Comprobación 3:

$9( \frac{35}{9} ) + 3 = 38 \\ ( \frac{9}{1} )( \frac{35}{9} ) + 3 = 38 \\ \frac{315}{9} + 3 = 38 \\ 35 + 3 = 38 \\ 38 = 38$