Question

Dada a função f(x)=x²- 5x+4, calcule:
a) f(-2)
b) f(1/2)
c) f(0) + f(4)

Answer 1

$a) f(-2)=(-2)^{2} -5.2+4 \\ f(-2)=4-10+4 \\ f(-2)=-2 \\ \\ \\ b)f( \frac{1}{2}) =( \frac{1}{2})^{2} -5. \frac{1}{2} +4 \\ f( \frac{1}{2})= \frac{1}{4} - \frac{5}{2}+4 \\ f( \frac{1}{2}) = \frac{1-10+16}{4} \\ f( \frac{1}{2})= \frac{7}{4} \\ \\ c)f(0)= 0^{2} -5.0+4 \\ f(0)=0-0+4 \\ f(0)=4\\ f(4)= 4^{2}-5.4+4 \\ f(4)=16-20+4 \\ f(4)=20-20=0 \\ f(0) + f(4) = 4+0 = 4$