Vynásobte:
$\huge 3xy^{2} \times 8x^{2}y^{3}= $
$ 3xy^{2} \times 8x^{2}y^{3}= 24x^{3}y^{5}$
$\huge 7xy^{2}z^{3} \times (-4xyz^{2})= $
$ 7xy^{2}z^{3} \times (-4xyz^{2})= - 28x^{2}y^{3}z^{5}$
$\huge 8n(3n-n^{2})=$
$8n(3n-n^{2})=24n^{2}-8n^{3}$
$\huge (6a^{2}-7ab)(-4ab^{3})=$
$(6a^{2}-7ab)(-4ab^{3})=-24a^{3}b^{3}+28a^{2}b^{4}$
$\huge (2x+3)(4+5x^{2})=$
$(2x+3)(4+5x^{2})=8x+10x^{3}+12+15^{2}$
$\huge (-3x+2)(-6+7x^{2})=$
$(-3x+2)(-6+7x^{2})=18x-21x^{3}-12+14^{2}$
Upravte:
$\huge 5a-3a(2b-9(+4b(8a-5)=$
$ 5a-3a(2b-9(+4b(8a-5)=5a-6ab+27a+32ab-20b=32a+26ab-20b$
$\huge (a-3)(2b-7)-(4-9a)(5b-1)=$
$(a-3)(2b-7)-(4-9a)(5b-1)=2ab-7a-6b+21-(20b-4-45ab+9a)=2ab-7a-6b+21-20b+4+45ab-9a=-16a-26b+47ab+25$
Upravte a ověřte správnost výpočtu dosazením x=-1:
$\huge 2x-3[2x-4(2x-5)]=$
$2x-3[2x-4(2x-5)]=2x-3[2x-8x+20]=2x-6x+24x-60=20x-60$
$x=-1$
$20.(-1)-60=-20-60=-80$
$2(-1)-3 [2(-1)-4(2(-1)-5)]=-2-3 (-2+28)=-2-3.26=-2-78=-80$
Zdroj: BUŠEK, Ivan a Marie KUBÍNOVÁ. Matematika. 1. vyd. Praha: Prometheus, 1994. Učebnice pro základní školy (Prometheus). ISBN 80-85849-58-5.