Question

Resolva em R as equações a seguir :
A) x+1 sobre X=3
B) (x-1).(x+3)= 5

Answer 1

A) x+1 sobre X=3 

x +1 = 3x
1 = 3x -x 
1 = 2x 
x = 1//2

B) (x-1).(x+3)= 5

x . x +x .3 -1.x -1.3 =5
x² +3x -x -3 = 5
x² +2x -3 -5 =0
x² +2x -8 = 0
a = 1  b = 2 c =-8

Δ=b² -4 .a.c
Δ=2²-4 .1.(-8)
Δ= 4 + 32
Δ= 36

x = -b+-√Δ/2a
x = -2 + - √36/2.1
x = -2 + -6/2

x' = -2 + 6/2
x' = 4/2
x' = 2

x" -2-4/2
x"-6/2
x"-3

S={-3;2}