Question

if f(x)=x2-5x+7 evaluate f(2)-f(-1)+f(1/3)

Answer 1

Substitute 2 in place of x in given expresion 2 square-5(2)+7=1 next (-1)square-5(-1)+7=12 finally 1/3 square - 5(1/3)+7=49/9 now finally 1-12+49/9=50/9

Answer 2

f(2) = 2² - 5(2) + 7
f(2) = 4 - 10 + 7
f(2) = 1

f(-1) = (-1)² - 5(-1) + 7
f(-1) = 1 + 5 + 7
f(-1) = 13

$f( \frac{1}{3} ) = {( \frac{1}{3} )}^{2} - 5( \frac{1}{3} ) + 7 \\ \\ f( \frac{1}{3} ) = \frac{1}{9} - \frac{5}{3} + 7 \\ \\ f( \frac{1}{3} ) = \frac{1 - 15 + 63}{9} \\ \\ f( \frac{1}{3} ) = \frac{49}{9} \\ \\ \\ \\ \\ \\ now \\ \\ \\ f(2) - f( - 1) + f( \frac{1}{3} ) \\ \\ => 1 - 13 + \frac{49}{9} \\ \\ => - 12 + \frac{49}{9} \\ \\ => \frac{ - 108 + 49}{9} \\ \\ => - \frac{59}{9}$