Answer:
Step-by-step explanation:
[tex](3x+4)(x^2+px+5) \\=3x^3+3px^2+15x+4x^2+4px+20\\=3x^3+(3p+4)x^2+(15+4p)x +20[/tex]
since we know that [tex]x^2[/tex] in this expansion is [tex]-23x^{2}[/tex]
thus [tex]3p+4=-23\\3p=-27\\p=-9[/tex]
Hope that helps!
