Question

resolva as equações exponenciais do tipo 2 3^(x+4)+3^(x+12)=90

Answer 1

3^(X - 4) + 3^(X + 12) = 90

elimanos numero tres

(X + 4) (x + 12) = 90

X^2 + 12X + 4X + 48 = 90

x^2 + 16X + 48 - 90 = 0

X^2 + 16X - 52 = 0

a = 1...b=16...c = - 52

FORMULA DELTA

D = b^2 - 4 a c

D = (16)^2 - 4 (1) (-52)

D = 256 - 4 (- 52)

D = 256 + 208

D = 464

FORMULA DE BRASKARA

X = - b + ,- \/D
......________
.............2a

X = - 16 +,- \/ 464
......___________
................2(1)

X = - 16 +,- 21,54
......__________
.................2

X' = - 16 + 21,54
......._________
................2

X' = 5,54
.......____
...........2

X' = 2,77

X" = - 16 - 21,54
........_________
................2

X" = - 37,54
......._______
...............2

X" = - 18,77

S = { - 18,77 , 2,77}