Answer:
a = 7
Explanation:
given
f(x) = 3x² + a and f(- 2) = 19
evaluate f(- 2) by substituting x = - 2 into f(x)
f(- 2) = 3(- 2)² + a = 3(4) + a = 12 + a
given f(- 2) = 19 , then equating gives
12 + a = 19 ( subtract 12 from both sides )
12 - 12 + a = 19 - 12 ( simplify both sides )
a = 7