Question

If, 5i - j ={a + b} i - {a - b} j then find a × b :-

Answer 1

Answer:6

(a+b)i-(a-b)j=5i-j,

Comparing equation on both sides , we get,

a+b=5

a-b=-1

Subtracting eq 1from eq2,

2a=4

a=2

b=5-2=3

So a*b=6