diketahui rumus f(x) = 3 - 7. jika f(a) = -13 maka nilai f(a + 13) =

jawab 
f(x)= 3x - 7

f(a)= - 13
3a - 7 = - 13
3a= - 6
a = - 2

f(a +13)= f(-2 +13)
= f(11) 
= 3(11) - 7
= 26