Question

What expression would you substitute for the variable x in the following system of equations:

x - 2y = 3
4x - 8y = 12

a) 3 - 2y
b) 4 - 8y
c) 3 + 2y
d) 4 + 8y

Answer 1

The expression to substitute for x in the system of equations is c) 3 + 2y, which is obtained by isolating x from the first equation.

Step-by-step explanation:

To determine which expression to substitute for the variable x in the system of equations x - 2y = 3 and 4x - 8y = 12, we can observe that the second equation is simply the first equation multiplied by 4. Therefore, the substitute for x that will satisfy both equations is the same expression in the first equation, isolated for x. This can be obtained by adding 2y to both sides of the first equation, resulting in the expression x = 3 + 2y. Hence, the correct option is c) 3 + 2y.