ANSWER
3(1 + x) = 2x + 9
EXPLANATION
We want to write an equation for the statement given.
To do this, we will take the statement phrase byphrased and then write the equation out.
So, we have that:
Three times the sum of one and a number
Let that number be x, then:
3 * (1 + x)
= 3(1 + x)
That is equal to twice the number plus 9:
Twice the number => 2 * x = 2x
That plus 9 is:
2x + 9
Therefore, the entire sentence, Three times the sum of one and a number is equal to twice the number plus 9 is:
3(1 + x) = 2x + 9
