Respuesta :

Answer:

48

Step-by-step explanation:

Given

4a² + 6a - 3(a + 4) + 15 ← distribute parenthesis

= 4a² + 6a - 3a - 12 + 15 ← collect like terms

= 4a² + 3a + 3 ← substitute a = 3 into the expression

= 4(3)² + 3(3)  + 3

= 4(9) + 9 + 3

= 36 + 9 + 3

= 48