x=10
First, remove the parentheses so it could turn into 150-2x-90=4x (the plus sign gets turned into a minus sign because of a certain rule.
Then do 150-90 which will result in 60-2x=4x.
Then subtract -4x on both sides. This will leave you with 60-6x=0.
Next, subtract 60 in both sides. This will leave you with -6x=-60.
Finally, divide by -6 on both sides. This will leave you with the answer x=10.