Question

Solve the system by substitution. If the system is inconsistent or has dependent equations, say so.

y = 5x
20x - 4y = 0

Answer 1

0

Explanation:

y = 5x

• 20 x - 4 y = 0

substitute the value of y in equation

• = 20x - 4 ( 5x ) = 0

multiply to get 20x

• = 20x - 20x = 0

collect like terms

• = 0

we can see here that 0 indeed equal 0.

so, system has an infinite solutions.

Answer 2

Dependent Equations

General Formulas and Concepts:

Pre-Algebra

Order of Operations: BPEMDAS

1. Brackets
2. Parenthesis
3. Exponents
4. Multiplication
5. Division
6. Addition
7. Subtraction

• Left to Right

Equality Properties

• Multiplication Property of Equality
• Division Property of Equality
• Addition Property of Equality
• Subtraction Property of Equality

Algebra I

• Terms/Coefficients
• Coordinates (x, y)
• Solving systems of equations by substitution/elimination

Explanation:

Step 1: Define Systems

y = 5x

20x - 4y = 0

Step 2: Solve for x

Substitution

1. Substitute in y [2nd Equation]: 20x - 4(5x) = 0
2. Multiply: 20x - 20x = 0
3. Combine like terms: 0 = 0

Here we see 0 does indeed equal 0.

∴ our systems has an infinite amount of solutions.