We need to find f(1)
f(1) means x=1
Now we look at the three inequalities and choose the one where x=1 satisfies
x<=-1 , -1<x<1 and x>=1
x=1 satisfies the inequality x>=1
so we use the third function to find f(1)
[tex]f(x) = 2x^2 + 3[/tex]
We plug in 1 for x and find f(1)
[tex]f(1) = 2(1)^2 + 3[/tex]= 2 + 3 = 5
f(1) = 5