Question

If f(x) = 3x2 + 2x – 8, then f(–2) = ?

Answer 1

Step-by-step explanation:

• f(x) = 3x2 + 2x - 8

------------->Then f(-2)

= f(x) : 3x2 + 2x - 8

= f(-2) : 3(-2)2 + 2(-2) - 8

= f(-2) : (-6)2 + (-4) - 8

= f(-2) : (-12) + (-4) - 8

= f(-2) : (-16) - 8

• f(-2) = -24 ✔

Answer 2

Step-by-step explanation:

f(x) = 3x2 + 2x – 8

———» Then f(-2)

f(-2) = 3(-2)^2 + 2(-2) - 8

f(-2) = 3((-2) × (-2)) + (2 × (-2)) - 8

f(-2) = 3(4) + (-4) - 8

f(-2) = (3 × 4) + (-4) - 8

f(-2) = 12 + (-4) - 8

f(-2) = 8 - 8

f(-2) = 0