Karla is given the equation 10x + 15 = 20 to solve. she says the solution is 1 2 . which reason justifies her solution? *a) karla says that to solve the equation you first add 15 and then multiply by 10. *b) karla says that to solve the equation you first multiply by 10 and then add 15. *c) karla says that to solve the equation you first subtract 15 and then divide by 10. *d) karla says that to solve the equation you first divide by 10 and then subtract 15