Solve each of these systems using the substitution method. make sure to check your answers !

2x + 3y = -4

x − 2y = 5

X -2y = 5
X -2y +2y = 5 +2y
X = 5 + 2y
Plug this into first formula.
2X + 3y = -4
2 (5 + 2y) +3y = -4
10 + 4y +3y = -4
10 + 7y = -4
10 -10 + 7y = -4 -10
7y = -14
7y/7 = -14/7
y = -2
Now plug Y back into 2x + 3y = -4
2x + 3(-2) = -4
2x -6 = -4
2x -6 +6 = -4 +6
2x = 2
2x/2 = 2/2
x = 1

Check by plugging X & y values in either formula.
2(1) + 3(-2) = -4
2 -6 = -4
-4 = -4

The density of the cube is 40