$\left(3-3x\right) \cdot \left(5+3x\right)$\left(3-3x\right) \cdot \left(5+3x\right)

$\left(15-3x\right)^{2}$\left(15-3x\right)^{2}

$\left(5-3x\right) \cdot \left(5+3x\right)$\left(5-3x\right) \cdot \left(5+3x\right)

$15-9x^2$15-9x^2