Question

how to learn to find the value of x if x=2 sum 90x + 3xx

Answer 1

if x=2,90*2+3*2*2=180+12=192

Answer 2

= 90x + 3xx (if x = 2)
= 90(2) + 3(2)(2)
= 180 + 3(4)
= 180 + 12
= 192.