Finding 3 unkown using 3 equation in variable form

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Hello

I have 3 equatons with 3 unknown θ2, θ3 and θ4 given below

x = a4 Cos θ1 Cos (θ2 + θ3+ θ4 ) + a3 Cos θ1 Cos (θ2 + θ3) + a2 Cos θ1 Cos θ2

y = a4 Sin θ1 Cos (θ2 + θ3+ θ4 ) + a3 Sin θ1 Cos (θ2 + θ3) + a2 Sin θ1 Cos θ2

z = a4 Sin (θ2 + θ3+ θ4 ) + a3 Sin (θ2 + θ3) + a2 Sin θ2

can you plz help me find value of θ2, θ3, θ4 in terms of x, y, z, a2, a3, a4 and θ1 (known variables)
I will be very thankful to you
Regards
Miko