Jika u = -2 i + 5 j dan v = 4 i + m, jika u tegak lurus v, maka nilai m adalah?​

Vektor

dua vektor saling tegak lurus → a • b = 0

u = -2i + 5j

v = 4i + mj

u ⊥ v

u • v = 0

(-2,5) • (4,m) = 0

-2.4 + 5.m = 0

-8 + 5m = 0

5m = 8

m = 8/5