Diketahui fungsi f(x) = 7x-15 dan g(x)=3x+20 maka nilai (f+g) (-1)

(f+g) (-1)= f(x)+g(x) (-1)
=7x-15+3x+20(-1)
=10x-5 (-1)
=10.(-1) -5
=-10-5
=5