Answer:
x = -13 and y = -4
Step-by-step explanation:
-4x + 8y = 20 ................... eqn 1
2x + 2y = -30 ................... eqn 2
Step 1: Multiply eqn 1 by 2 and eqn 2 by 4
(-4x + 8y = 20) × 2
(2x + 2y = -30) × 4
we will have
-8x + 16y = 40 ....................eqn 3
8x + 4y = - 120 .................. eqn 4
Step 2: Add eqn 3 and 4 together
20y = - 80
Step 3: divide all through by 20
y = -80/20
y = -4
Step 4: Substitute -4 for y in eqn 1
-4x + 8(-4) = 20
-4x - 32 = 20
-4x = 20 + 32
-4x = 52
Step 5: Divide both sides by -4
x = 52/-4
x = -13
Answer:
{x,y} = {-35/3,-10/3}
Step-by-step explanation:
-4x+8y=20;2x+2-30
System of Linear Equations entered :
[1] -4x + 8y = 20
[2] 2x + 2y = -30
Solve by Substitution :
// Solve equation [2] for the variable y
[2] 2y = -2x - 30
[2] y = -x - 15
// Plug this in for variable y in equation [1]
[1] -4x + 8•(-x -15) = 20
[1] -12x = 140
// Solve equation [1] for the variable x
[1] 12x = - 140
[1] x = - 35/3
// By now we know this much :
x = -35/3
y = -x-15
// Use the x value to solve for y
y = -(-35/3)-15 = -10/3
Solution :
{x,y} = {-35/3,-10/3}
