f(x) =2x³+ax²+20x+10 dibagi oleh (2x-1) sisa 18

jwab

suku banyak

f(x) = 2x³+ ax² + 20x + 10
dibagi (2x -1) =0 --> x = 1/2 
sisa 18

f(1/2) = 18
2(1/2)³ + a (1/2)² + 20 (1/2) + 10 = 18
2 (1/8) + 1/4 a + 10 + 10 = 18
1/4 + 1/4 a + 20 = 18 ...kali 4
1 +  a + 80 = 72
a + 81 = 72
a = 72 - 81
a = - 9