Answer: 2*(2.5 + 4.7 + c)
Step-by-step explanation:
We want to write
"Twice the sum of 2.5, 4.7 and a number c"
First:
"... the sum of 2.5, 4,7 and a number c" is written as:
2.5 + 4.7 + c
And twice "something" is written as:
2*something.
Then:
"Twice the sum of 2.5, 4.7 and a number c"
is:
2*(2.5 + 4.7 + c)
