two equations, need solve symbolically in Mupad for a variable and getting errors

I have two equations:

RA := (KA1-bA1*pA1+aB1*pB1)*(pA1)-YA1*[KA1-bA1*pA1+aB1*pB1]^2
RB := (KB1-bB1*pB1+aA1*pA1)*(pB1)-YB1*[KB1-bB1*pB1+aA1*pA1]^2

and I need a closed form solution for pA1 and pB1, symbolically. I have tried various solve commands in which I get an error "equation is an unknown type" and if I try linsolve I get that the equations are not linear. I am not sure how to go about this. I feel like it should be simple.

Answer 1

[Walter Roberson]

Do not use [] for brackets: it means list-building.

RA := (aB1*pB1-bA1*pA1+KA1)*pA1-YA1*(aB1*pB1-bA1*pA1+KA1)^2;
RB := (aA1*pA1-bB1*pB1+KB1)*pB1-YB1*(aA1*pA1-bB1*pB1+KB1)^2;
solve([RA,RB],[pA1,pB1])

there are 4 solutions that are not complicated.

Possibly though what you mean is

eqn1 := RA = (aB1*pB1-bA1*pA1+KA1)*pA1-YA1*(aB1*pB1-bA1*pA1+KA1)^2;
eqn2 := RB = (aA1*pA1-bB1*pB1+KB1)*pB1-YB1*(aA1*pA1-bB1*pB1+KB1)^2;
solve([eqn1, eqn2], [pA1,pB1])

The solutions to this are complicated, involving quartics