What does twice the product of 3 and a number exceeds the sum of the number and 80 by 10. what is that number?

Let x be the number

twice the product of 3 and a number means

2 (3x)

the sum of the number and 80 by 10 means

x+80+10

putting this altogether creates an equation

2 (3x) = x+80+10

6x=x+90 (expanded the brackets on the left hand side and added 80 + 10 on the left)

5x=90 (subtracted x to both sides)

x=90/5

x=18

Therefore the number is 18.

So 2 (3x) = x+80+10

distribute

6x=x+90

subtract x from both sides

5x=90

divide both sides by 5

x=18