7. Write each expression in exponential form. a) (5 x 5 x 5) x (5 x 5 x 5) x (5 x 5 x 5) x (5 × 5 ×,5)
b) [(-9) × (-9)] x [(-9) × (-9)] × [(-9) × (-9)] x [(-9) × (-9)] × [(-9) × (-9)]​