Grade 7 Algebraic Expressions Worksheets From the following expressions 3ab, a2, b2, a, 5ab, -2ab, 2a2 the three like terms are: 11. The value of 21b - 32 + 7b - 20b is: 12. The value of expression 7a - 4b for a = 3, b = 2 is: 13. Factors of the term 15x2 in the expression 15x2 - 13x are: 14. Factors of the terms -4pq2 in the expression 9p2q2 - 4pq2 are: