2d 143 Dari langkah 1, kita dapatkan a + 2d = 14. Dari langkah 2, kita dapatkan 2a + 6d = 34Divide both sides of the equation by the coefficient of variable: d = 14 2 d = dfrac{14}{2} d = 2 14 Cross out the mon factor: d = 7 d = 7 d