Answer:
x = 612
Step-by-step explanation:
x = 2(y + z) Divide by 2 to isolate y + z
x/2 = y + z Set up the sum of three numbers
x + y + z = 918 Substitute x / 2 for y + z
x + x/2 = 918 Combine like terms
3/2 x = 918 Multiply both sides by 2/3
2/3 * 3x/2 = 2/3 * 918
x = 612
