Toán Lớp 8: Bài 1 (4đ): Thực hiện phép tính
а) 5хy.(3x*y — 2ху +4)
b) (2x-3).(- х2— 2х – 1)
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Toán Lớp 8: Bài 1 (4đ): Thực hiện phép tính
а) 5хy.(3x*y — 2ху +4)
b) (2x-3).(- х2— 2х – 1)
Comments ( 2 )
=2x^3y^2+6x^2y-10x^2y^2z
b) ( 3x – 5)(9x² + 12x + 16)
=27x^3+36X^2+48x-45X^2-60X-80
= 27x^3-9x^2-12x-80
с) x(x^2 + 3x + 1) — х^2.(х+3)
=x^3+3x^2+x-x^3-3x^2
=x
d) (x – 2)^2 + x (4 – x)
=X^2-4x+4+4x-x^2
=4
e) (х- 7)(х + 7) – (х – 2)
=x^2-49-x+2
=x^2-x-47