Respuesta :

gmany

Answer:

460

Step-by-step explanation:

We know:

LCM(a, b) · HCF(a, b) = a · b

We have:

HCF(6, x) = 2 and LCM(6, x) = 60.

Substitute:

60 · 2 = 6 · x

120 = 6x             divide both sides by 6

20 = x → x = 20

Substitute to x² + 3x:

20² + 3(20) = 400 + 60 = 460