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2 years ago

Solve by using substitution -5x-y=12 y=-4x-9

Mathematics

1 answer:

tresset_1 [31]2 years ago

4 0

Answer:

(-3, 3)

General Formulas and Concepts:

Pre-Algebra

Order of Operations: BPEMDAS
Equality Properties

Algebra I

Solving systems of equations using substitution/elimination

Step-by-step explanation:

Step 1: Define systems

-5x - y = 12

y = -4x - 9

Step 2: Solve for x

Substitution

Substitute in y: -5x - (-4x - 9) = 12
Distribute negative: -5x + 4x + 9 = 12
Combine like terms: -x + 9 = 12
Subtract 9 on both sides: -x = 3
Divide -1 on both sides: x = -3

Step 3: Solve for y

Define original equation: y = -4x - 9
Substitute in x: y = -4(-3) - 9
Multiply: y = 12 - 9
Subtract: y = 3

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