If x + 2y = 10 and y = 3, what is x?

To find the value of ( x ) given the equations ( x + 2y = 10 ) and ( y = 3 ), we first substitute the value of ( y ) into the equation.

By substituting ( y = 3 ) into the equation ( x + 2y = 10 ), we replace ( y ) with ( 3 ), which gives us:

[ x + 2(3) = 10 ]

This simplifies to:

[ x + 6 = 10 ]

Next, we isolate ( x ) by subtracting ( 6 ) from both sides:

[ x = 10 - 6 ]

This leads us to:

[ x = 4 ]

Thus, the correct answer is that ( x = 4 ). This result is confirmed by substituting back into the original equation to ensure it satisfies ( x + 2y = 10 ), maintaining the integrity of the solution.