Resposta :
[tex]a)\\\left(x+2\right)\left(x+3\right)\\\\=xx+x\cdot \:3+2x+2\cdot \:3\\\\=xx+3x+2x+2\cdot \:3\\\\=x^2+5x+6[/tex]
[tex]b)\\\left(a-2\right)\left(a-7\right)\\\\=aa+a\left(-7\right)+\left(-2\right)a+\left(-2\right)\left(-7\right)\\\\=aa-7a-2a+2\cdot \:7\\\\=a^2-9a+14[/tex]
[tex]c)\\\left(y+6\right)\left(y-6\right)\\\\=y^2-6^2\\\\6^2=36\\\\=y^2-36[/tex]
Explicação passo-a-passo:
A) x²+ 3x + 2x + 6 = x² + 5x + 6
B) a² - 7a - 2a + 14 = a² - 9a + 14
C) y² - 6y - 6y - 36 = y² - 12y - 36