Chapter 6 - Section 6.3 - Factoring Trinomials of the Form ax2+bx+c - Exercise Set - Page 436: 76

$(r^2-5)(4r^2+3)$

$4r^4-17r^2-15$ Factors of -15: 1 and -15, 3 and -5, 5 and -3, 15 and -1 Factors of 4: 1 and 4, 2 and 2, -1 and -4, -2 and -2 $(r^2-5)(4r^2+3)$ $r^2*4r^2+3*r^2+4r^2*-5+3*-5$ $4r^4+3r^2=20r^2-15$ $4r^4-17r^2-15$