Answer:
[tex](x + 7) \times (3x - 4)[/tex]
Step-by-step explanation:
[tex] {3}^{2} + 17x - 28[/tex]
[tex]3 {x}^{2} + 21x - 4x - 28[/tex]
[tex]3 \times x(x + 7) - 4x - 28[/tex]
[tex]3x \times ( x + 7) - 4(x + 7)[/tex]
[tex](x + 7) \times (3x - 4)[/tex]