Question

Найдите значение выражения : б) 2-7х^2 при =-1/2

Answer 1

$f(x)=2-7x^2$

$f(- \frac{1}{2} )=2-7*(-\frac{1}{2})^2=2-7*(\frac{1}{2})^2=2-7*\frac{1^2}{2^2}=2-7* \frac{1}{4}=$

$=2*\frac{4}{4} - \frac{7*1}{4} = \frac{2*4}{4} - \frac{7}{4} = \frac{8-7}{4} = \frac{1}{4} =0.25$