Answer:
(-2, 6)
General Formulas and Concepts:
Pre-Algebra
- Order of Operations: BPEMDAS
- Equality Properties
Algebra I
- Solving systems of equations using substitution/elimination
- Solving systems of equations by graphing
Explanation:
Step 1: Define systems
4x - 2y = -20
7x + 2y = -2
Step 2: Rewrite systems
4x - 2y = -20
- Add 2y to both sides: 4x = 2y - 20
- Divide 4 on both sides: x = 1/2y - 5
Step 3: Redefine systems
x = 1/2y - 5
7x + 2y = -2
Step 4: Solve for y
Substitution
- Substitute in x: 7(1/2y - 5) + 2y = =-2
- Distribute 7: 7/2y - 35 + 2y = -2
- Combine like terms: 11/2y - 35 = -2
- Add 35 to both sides: 11/2y = 33
- Isolate y: y = 6
Step 5: Solve for x
- Define original equation: 7x + 2y = -2
- Substitute in y: 7x + 2(6) = -2
- Multiply: 7x + 12 = -2
- Subtract 12 on both sides: 7x = -14
- Divide 7 on both sides: x = -2
Step 6: Graph systems
Check the system.