u4 = 1 u7=-8 nilai a dan nilai b ?

U7 - U4 = -8 - 1
7b - 4b = -9
3b = -9
b = -9/3
b = -3

➡Nilai b = -3

U4 = 1
a + (4-1)b = 1
a + 3(-3) = 1
a = 1 + 9
a = 10

➡Nilai a = 10

[tex]b = \frac{u7 - u4}{7 - 4} = \frac{ - 8 - 1}{3} = - 3 \\ u4 = 1 \\ a + 3b = 1 \\ a + 3( - 3) = 1 \\ a = 1 + 9 \\ a = 10[/tex]