Question

como calcular f(x)=x²+5x+4

A) f(-2)

B) $\frac{1}{2}$

C) (0)+ f(4)

Answer 1

f(x) = x² + 5x + 4

f(-2) = (-2)² + 5.(-2) + 4
f(-2) = 4 - 10 + 4
f(-2) = -2

f($\frac{1}{2}$) = $\frac{1}{2}$² + 5.($\frac{1}{2}$) + 4
f($\frac{1}{2}$) = $\frac{1}{4}$ + 2,5 + 4
f($\frac{1}{2}$) = 0,25 + 2,5 + 4
f($\frac{1}{2}$) = 6,75 

f(0) + f(4)
f(0) = 0² + 5.0 + 4
f(0) = 4

f(4) = 4² + 5.4 + 4
f(4) = 16 + 20 + 4
f(4) = 40

f(0) + f(4) = 4 + 40
f(0) + f(4) = 44

Answer 2

a.
f(-2) = x² + 5x + 4
f(-2) = (-2)² + 5 * (-2) + 4
f(-2) = 4 - 10 + 4
f(-2) = -2

b.
f(1/2) = (1/2)² + 5 * 1/2 + 4
f(1/2) = 1/4 + 5/2 + 4
f(1/2) = (1+5+16)/4
f(1/2) = 27/4

c.
f(0) = 0² + 5 * 0 + 4
f(0) = 4

f(4) = 4² + 5 * 4 + 4
f(4) = 16 + 20 + 4
f(4) = 36 + 4
f(4) = 40

f(0) + f(4) = 4 + 40 = 44