Factoring by grouping how do i solve it 8r^3-64^2+r-8

Squaring a number is the same as multiplying the number by itself (64⋅64). In this case, 64 squared is 4096.

8 r^3 - 4096+r-8

Subtract 8 from - 4096 to get - 4104.

8 r^3 - 4104+r

Factor the polynomial using the rational roots theorem.

(r-8) (8 r^2 + 64r+513)