diketahui rumus fungsi f(X) = 2x-7 Jika f(a) = -1 dan f( 4 )= b maka nilai 2a-b adalah

f(a)=2x-7=-1
2a-7=-1
2a = 6
a = 3
f(4) = b

2a-b = 2.3-4
= 6-4
= 2

f(a) = -1
-1 = 2(a)-7
-1+7 = 2(a)
6 = 2a
a = 3

f(4)= b
f(4)= 2(4)-7
f(4) = 8-7
f(4) = 1
b = 1

maka 2a-b = 2(3)-1
= 6-1
=5