Simplify by dividing both sides of the equation by 16.
-(10u-90)=2(8u+71)
Open the brackets. Minus outside first bracket changes - to + inside.
-10u+90=16u+142
Gather the knowns on one side of the equals and the unknowns on the other. Remember that when you cross from side of the equation to the other, minus changes to plus and plus to minus. So 16u on the right becomes -16u on the left, and 90 on the left becomes -90 on the right. The u's on the left just get more negative.
-26u=52
Divide both sides by 26.
-u=2
Take the minus over leaving u=-2, the answer. Check the answer by substituting u=-2 in the original equation.
-16*(-20-90)=32*(-16+71)
-16*-110=32*55 is the same as 16*110=32*55 (minus times minus is plus)
110=(32/16)*55 = 110 (because 32/16=2)
110=110 so answer is correct.