Question

Se f(x)= -2x+9, então o valor de f(1) - f(3) é?

Answer 1

f(x)= -2x+9

f(1) - f(3)=

[f(1)= -2×1+9] - [f(3)=-2×3+9]

[f(1)= -2+9] - [f(3)= -6+9]

[f(1)= 7] - [f(3)= 3]

f(1) = 7

f(3) = 3

f(1) - f(3) =

7 - 3 = 4