Com es resol el sqrt (3x) + 8 = x + 2?

Resposta:

# x = {3,12} #

#sqrt (3x) + 8 = x + 2 #

#sqrt (3x) = x + 2-8 #

#sqrt (3x) = x-6 #

# (sqrt (3x)) ^ 2 = (x-6) ^ 2 #

# 3x = x ^ 2-12x + 36 #

# x ^ 2-12x-3x + 36 = 0 #

# x ^ 2-15x + 36 = 0 #

# (x-12) (x-3) = 0

# "si (x-12) = 0 llavors x = 12"

# "si (x-3) = 0 llavors x = 3"

# x = {3,12} #

3 i 12

#sqrt (3x) + 8 = x + 2 #

Aïlleu el terme radical.

#sqrt (3x) = x - 6 #

Plaça dels dos costats:

# 3x = (x - 6) ^ 2 = x ^ 2 - 12x + 36 #

# x ^ 2 - 15x + 36 = 0 #

Cerqueu 2 nombres (arrels reals) que sàpiguen la suma (15 = -b) i el producte (c = 36). Són: 3 i 12.