To solve for x and y, we can use the method of either substitution or elimination.

Using the substitution method:
From the first equation, we can solve for x in terms of y:
4x + 15y = -42
4x = -15y - 42
x = (-15y - 42)/4

Now, substitute x in the second equation:
-6(-15y - 42)/4 + 25y = -32
90y + 252 - 100y = -32
-10y + 252 = -32
-10y = -284
y = 28.4

Now, substitute y back into the equation to solve for x:
4x + 15(28.4) = -42
4x + 426 = -42
4x = -468
x = -117

Therefore, the solution is x = -117 and y = 28.4.

Using the elimination method:
Multiply the first equation by 6 and the second equation by 4 to eliminate x when adding the two equations together:
24x + 90y = -252
-24x + 100y = -128

Now, add the two equations:
190y = -380
y = -2

Now, substitute y back into the equation to solve for x:
4x + 15(-2) = -42
4x - 30 = -42
4x = -12
x = -3

Therefore, the solution is x = -3 and y = -2.