Let the x represent the unknown number.
"2 times a number" is 2x
"The sum of 2 times a number and 11" is 2x + 11
"The sum of 2 times a number and 11 is -7" is 2x + 11 = -7
Now we solve the equation for x to find the unknown number.
2x + 11 = -7
Subtract 11 from both sides.
2x = -18
Divide both sides by 2.
x = -9
Answer: The number is -9.
Check: 2 times -9 = -18
-18 + 11 = -7
The answer is correct.