Find two elements which give a fixed sum

I tried to solve this problem:

find the value of both x1 and x2 in the following expression

c1= a1*x1+a2*x2

where:

c1 is a given value

a1 and a2 are constants

x1 is bounded between 1400 and 1650

x2 is bounded between 95 and 195

I tried to use linear programming optimization with equality constrain but seems to not work.

It seems a really simple problem for me but I am not able to produce a code so solve it

Thanks for your help and time