Question

-0.7x-0.16y=-4 5x+2y=20 solve for x and y

Answer 1

one method is by substitution
using the second eqn y = (20-5x) / 2
using this value of y in the first eqn
-0.7x-0.16(20-5x)/2 = -4
-0.7x -1.6+0.4x = -4
solve for x
with this value of x put in either of the original eqn and solve for y

Answer 2

x=8 an y = -10 use any original eqn to verify the solution
check in eqn 1
left side
-0.7(8) -0.16(-10) = -5.6 --1,6 = -5.6 + 1.6 = -4
right side = -4

if you use eqn 2
5x + 2y = 20
5(8)-2(-10) =20
40-20 = 20
20 = 20
therefore it is verified and correct