I'm writing here because I have no idea how to solve this equation. I tried to solve it before using the "Equation balance tool" on this website, but I found all strange numbers such as 225H3PO4 and 75Mn(H2PO4)2 and I don't think that's correct. By using the tool it seems that are negative coefficients and I don't think that the equation is wrong .
Please help me, I'll be really grateful!!