Someone please help me understand this solution.

There are only 2 equations but 3 variable, so somehow we need to do something so that when we add them the variables are equaly so we take out common and get x+y+z

Now the first equation's coefficients increase by 7

in second they decrease by 4

so if you reverse it and multiply by 4 ( in eq1) and by 7 ( in eq 2) and then add them, your coeeficients would be same ( 181 in this case)

[ please Mark it as correct if you understand :) ]

hey so actually this is a pattern that i personally just learnt directly aise hi. basically, if you have 3 variables, and only 2 eqn, u cant find the values of x,y and z separately. however, if the 2 eqn youre given have coefficients that are in AP, you have to find the common difference and multiply that with the other eqn. like for example here, eqn 1 has d of 7, so u multiple eqn 2 with that and vice versa. the eqns u have then can be either added or subtracted and doing that will give you the value of x+y+z.