Verified answer

1) 126 000 = 1,26 * 10⁵

2) 0,0035 = 3,5 * 10⁻³

3) a⁷ * a⁻⁵ = a⁷⁻⁵ = a²

4) a⁻¹⁰ : a⁻¹³ = a⁻¹⁰⁻⁽⁻¹³⁾ = a⁻¹⁰⁺¹³ = a³

5) (a⁹)⁻² * a²⁰ = a⁻¹⁸ * a²⁰ = a⁻¹⁸⁺²⁰ = a²