Question

1) resolva o sistema de equação $\left \{ {{2x+3y=14} \atop {x+y=6}} \right.$ 

2)  2(2x-3)<-3x+1

3) se f(x)=6x+2 qual o valor de x para que f(x)=14

Answer 1

1) 
$\left \{ {{2x +3y=14} \atop {x+y=6}} \right. \\ \\ \left \{ {{2x +3y=14} \atop {x+y=6(.-2)}} \right. \\ \\ \left \{ {{2x +3y=14} \atop {-2x-2y=-12}} \right. (+) \\ \\ 3y-2y=2 \\ y=2 \\ \\ x+y=6 \\ x=6-y \\ x=6-2 \\ x=4$

∴ x = 4 e y = 2

2) 2(2x-3)<-3x+1
4x - 6 < -3x + 1
7x < 7

∴ x < 1

3) se f(x)=6x+2 qual o valor de x para que f(x)=14

f(x)=6x+2
14 = 6x + 2
6x = 12

∴ x = 2