If x [ - 5 { - 4 ( - a ) } ] + 6 [ - 3 { -3 ( - a ) } ] = 6a, then the value of x is:

Correct option is A

Given:​

x [ - 5 { - 4 ( - a ) } ] + 6 [ - 3 { -3 ( - a ) } ] = 6a

Solution:​

x [ - 5 { 4a} ] + 6 [ - 3 {3a } ] = 6a

x [ - 20 a ] + 6 [ - 9a] = 6a

-20 ax - 54a = 6a

-20 ax = 6a + 54a

-20 ax = 60a

x = $$-\frac{60a}{20a}= -3$$​​