Question

Por favor preciso disso para amanhã me ajudem!!

a) y=x+3
y=2x+6

b)2x+y= 7
x+3y=11

Answer 1

a)
$y = x + 3 \\ y = 2x + 6 \\ x + 3 = 2x + 6 \\ 2x - x = 3 - 6 \\ x = - 3 \\ \\ y = x + 3 \\ y = - 3 + 3 \\ y = 0$
b)
$2x + y = 7 \\ y = 7 - 2x \\ \\ x + 3y = 11 \\ x + 3(7 - 2x) - 2x = 11 \\ x + 21 - 6x - 2x = 11 \\ - 7x = 11 - 21 \\ 7x = 10 \\ x = \frac{10}{7} \\ \\ y = 7 - 2x \\ y = 7 - 2 \times \frac{10}{7} \\ y = 7 - \frac{20}{7} \\ \frac{7y}{7} = \frac{49}{7} - \frac{20}{7} \\ 7y = 39 \\ y = \frac{39}{7}$