Algunas preguntas sobre la tarea de verano de New Thinking Mathematics de séptimo grado: 1. (2A+3B-1) (2A-3B+1) 2. (3A-1) (2A-3)+(6A-5) (A-4).
1..(2a+3b-1)(2a-3b+1)
=[2a+(3 b-1)][2a-(3 b-1)]
=4aa-(3b-1)(3b-1)
=4aa-9bb+6b-1
2.(3y-1)(2y-3)+( 6y-5)(y-4)
= 6yy-11y+3+6yy-29y+20
=12yy-40y+23
3. (x-1)(x+3)-x(x-2)
=xx+2x-3-xx+2x
=4x-3