Question

Calcule as raizes das funçoes:
a) f(x)=25x-200 b)f(x)=x²+3x+2

Answer 1

a) 25x = 200
 
x= 200/25
x = 8 

b) x²+3x+2

A=1
B=3
C=2

B²- 4*A*C

3² - 4*1*2
9 - 8
= 1

(-B +-  √1) / 2*A

x' = (-3 + 1)/ 2 = -2/2 = -1

x" = (-3-1)/2 = -4/2 = -2  

{-1,-2} 

Answer 2

a) f(x)=25x-200
25x-200= 0
25x=200
x=200 /25
x=8


b)f(x)=x²+3x+2
x²+3x+2=0
a= 1 ; b= 3 ; c=2
∆ = b² - 4 . a . c
∆ = (3)² - 4 . (1) . (2)
∆ = 9 - 8
∆ = 1
x = -b ± √∆) / 2.a
x = - (3)± √1/2 (1)
x = - 3± 1/2

x' = - 3+1/2
x'= - 1

x" = - 3 -1/2
x"= - 2