Anja simplified the expression StartFraction 10 x Superscript negative 5 Baseline Over Negative 5 x Superscript 10 Baseline EndFraction to StartFraction 15 Over x Superscript 15 Baseline EndFraction. What mistake did Anja make? She divided the exponents instead of subtracting them. She divided the coefficients instead of subtracting them. She subtracted the coefficients instead of dividing them. She subtracted the exponents instead of dividing them.