Question

30 pontos para qm responder

a) 6X=2X+6:
b) 2X-5=x+1:
c) 2X+3=X+4:
d) 5X+7=4x+10
e) 4X-10=2X+2:
f) 4x-7=8x2
​

Answer 1

• Letra A

$\sf 6x = 2x + 6$

$\sf 6x - 2x = 6$

$\sf 4x = 6$

$\sf x = \dfrac{6}{4}$

$\sf x = \dfrac{6^{ \div 2} }{4^{ \div 2} }$

$\red{\boxed{\sf x = \dfrac{3}{2} }}$

• Letra B

$\sf 2x - 5 = x + 1$

$\sf 2x - x = 1 + 5$

$\red{\boxed{\sf x = 6}}$

• Letra C

$\sf 2x + 3 = x + 4$

$\sf 2x - x = 4 - 3$

$\red{\boxed{\sf x = 1}}$

• Letra D

$\sf 5x + 7 = 4x + 10$

$\sf 5x - 4x = 10 - 7$

$\red{\boxed{\sf x = 3}}$

• Letra E

$\sf 4x - 10 = 2x + 2$

$\sf 4x - 2x = 2 + 10$

$\sf 2x = 12$

$\sf x = \dfrac{12}{2}$

$\red{\boxed{\sf x = 6}}$

• Letra F

$\sf 4x - 7 = 8 {x}^{2}$

$\sf 8 {x}^{2} = 4x - 7$

$\sf 8 {x}^{2} - 4x + 7 = 0$

$\sf x_{½} = \dfrac{ - b\pm \sqrt{\Delta} }{2a}$

$\sf x_{½} = \dfrac{ - ( - 4)\pm \sqrt{( - 4)^{2} - 4\cdot 8\cdot 7 } }{2\cdot 8}$

$\sf x_{½} = \dfrac{ 4\pm \sqrt{16- 224 } }{16}$

$\sf x_{½} = \dfrac{ 4\pm \sqrt{ - 208} }{16}$

$\red{\boxed{\sf x \notin \mathbb{R}}}$