Question

PLEASE HELP FAST! Solve for Y in the following system of equations!

X-y=-1
3x+5y=21
A.) 2
B.) 3
C.) 9
D.) 12

Answer 1

B.) 3

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

Algebra I

• Solving systems of equations using substitution/elimination

Explanation:

Step 1: Define Systems

x - y = -1

3x + 5y = 21

Step 2: Rewrite Systems

x - y = -1

1. Add y to both sides: x = y - 1

Step 3: Redefine Systems

x = y - 1

3x + 5y = 21

Step 4: Solve for y

Substitution

1. Substitute in x: 3(y - 1) + 5y = 21
2. Distribute 3: 3y - 3 + 5y = 21
3. Combine like terms: 8y - 3 = 21
4. Add 3 to both sides: 8y = 24
5. Divide 8 on both sides: y = 3