5x -9y =-26
-2x +3y =11

(-7, -1)

General Formulas and Concepts:

Pre-Algebra

Order of Operations: BPEMDAS

Brackets Parenthesis Exponents Multiplication Division Addition Subtraction Left to Right

Equality Properties

Multiplication Property of Equality Division Property of Equality Addition Property of Equality Subtract Property of Equality

Algebra I

Solving systems of equations using substitution/elimination

Step-by-step explanation:

Step 1: Define Systems

5x - 9y = -26

-2x + 3y = 11

Step 2: Rewrite Systems

-2x + 3y = 11

Multiply everything by 3:                    -6x + 9y = 33

Step 3: Redefine Systems

5x - 9y = -26

-6x + 9y = 33

Step 4: Solve for x

Elimination

Combine 2 equations:                    -x = 7Divide -1 on both sides:                  x = -7

Step 5: Solve for y

Define equation:                    5x - 9y = -26Substitute in x:                       5(-7) - 9y = -26Multiply:                                  -35 - 9y = -26Add 35 on both sides:           -9y = 9Divide -9 on both sides:        y = -1

  put the amount of $8 a pound chocolate as say it as x
 As the total number of pounds is 20
so the amount of $3 a pound chocolate must be 20−x
so it will be.
8x + 3(20 - x) = 5(20)
so correct option is C
hope it helps