The value of x is -4.186
Solution:
Given equations,
[tex]-3x-8y=20\rightarrow(1)[/tex]
[tex]-5x+y=20\rightarrow+y=20+5x\rightarrow (2)[/tex]
On substituting (2) in (1) we get,
-3x-8(20+5x)=20
-3x-160-40x=20
On solving we get,
-160-43x=20
-43x=20+160
On grouping the known and unknown terms,
x=180/-43
x=-4.1860