fungsi f didefinisikan dengan rumus f(x) = ax + b. jika f(-3)= -15 dan f(2)=0, maka gentleman nilai f(-5)!

f(-3) = -3a + b = -15
f(2 ) = 2a + b = 0
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-5a = -15
a = -15/-5 = 3
2(3) + b = 0
6 + b = 0
b = -6