1. Simplify: 3x-5x+7x 2. Simplify: -3(2x - 7y) 3. Simplify: 2x-3(x-2) 4. Simplify: 2x + 3[4-(3x-7)] 5. Simplify: 3x-7y - 12x 6. Evaluate b 3ab when a 3 and b = -2. - 7. Simplify: (10x) 8. Simplify: 5(2x+4)-3(x-6) -2ab 11. Evaluate when a -4 and b = 6. 12. Simplify: (12x) 2b a 13. Simplify: -7y+ 6y - (-2y) 14. Simplify: -2(2x-4) 15. Simplify: (-15a) 16. Simplify: -2[x-2(x - y)] + 5y 19. Translate "the difference between the squares of a and b" into a variable expression. 20. Translate "ten times the difference between a number and three" into a variable expression. Then simplify. 21. Translate "the sum of a number and twice the square of the number" into a variable expression. 22. Translate "three less than the quotient of six and a number" into a variable expression. 23. Translate "b decreased by the product of b and 7" into a variable expression. 24. Sports The speed of a pitcher's fastball is twice the speed of the catcher's return throw. Express the speed of the fastball in terms of the speed of the return throw. 25. Metalwork A wire is cut into two lengths. The length of the longer piece is 3 in. less than four times the length of the shorter piece. Express the length of the longer piece in terms of the length of the shorter piece. O Shaun Best/Reuters