Grade 8 — Solve each equation for x (all answers are whole numbers). For #7–8, write the equation first. Check every answer by substituting.
1. 2x + 8 = 3x + 2
2. 5x − 9 = 2x + 12
3. 3(x + 4) = 2x + 18
4. 4x + 5 = 7x − 13
5. x/2 + 7 = 13
6. 6x − 4 = 3x + 17
7. Contest registration costs $15 plus $4 per division entered. Write an equation for the total cost C for d divisions.
8. A yo-yo workshop charges a $20 flat fee plus $5 per yo-yo kit. Write an equation for the total cost T for k kits.
| 1. x = 6 (12+8 = 20; 18+2 = 20 ✓) | 2. x = 7 (35−9 = 26; 14+12 = 26 ✓) |
| 3. x = 6 (3×10 = 30; 12+18 = 30 ✓) | 4. x = 6 (24+5 = 29; 42−13 = 29 ✓) |
| 5. x = 12 (12÷2+7 = 6+7 = 13 ✓) | 6. x = 7 (42−4 = 38; 21+17 = 38 ✓) |
| 7. C = 15 + 4d | 8. T = 20 + 5k |