Given y = 2x + 3, what is y when x = 4?

Given y = 2x + 3, what is y when x = 4?

• A. y = 10
• B. y = 11
• C. y = 12
• D. y = 9

Answer: (B)

Evaluating a linear expression at a given input by substitution. Plug in the value x = 4 into y = 2x + 3: multiply 2 by 4 to get 8, then add 3 to get 11. So y equals 11. The other values would require different x: for example, y = 10 would need x = 3.5, y = 12 would need x = 4.5, and y = 9 would need x = 3.

Evaluating a linear expression at a given input by substitution. Plug in the value x = 4 into y = 2x + 3: multiply 2 by 4 to get 8, then add 3 to get 11. So y equals 11. The other values would require different x: for example, y = 10 would need x = 3.5, y = 12 would need x = 4.5, and y = 9 would need x = 3.