Let's break down the problem step by step to answer both questions.
Question 1: Identifying the System of Linear Equations.
We're given two scenarios, which we need to represent as equations:
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5 small tables and 8 chairs for $115: This can be expressed as: \[ 5x + 8y = 115 \] where \(x\) is the cost of each table and \(y\) is the cost of each chair.
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3 small tables and 5 chairs for $70: This can be expressed as: \[ 3x + 5y = 70 \]
So the system of linear equations that represents these two scenarios is: \[ \begin{align*} 5x + 8y &= 115 \quad \text{(Equation 1)} \ 3x + 5y &= 70 \quad \text{(Equation 2)} \end{align*} \]
Looking at the responses:
- Response B: \(5x + 8y = 115; , 3x + 5y = 70\) matches our equations.
Thus, the answer to Question 1 is B.
Question 2: Solving the System of Equations.
Now we can solve the system of equations:
- From the first equation: \[ 5x + 8y = 115 \]
- From the second equation: \[ 3x + 5y = 70 \]
We will use the substitution or elimination method. Let's use elimination.
Multiply the second equation by 1.6 (to match the coefficients of \(y\)): \[ 1.6(3x + 5y) = 1.6(70) \ 4.8x + 8y = 112 \]
Now we have: \[ 5x + 8y = 115 \quad \text{(1)} \ 4.8x + 8y = 112 \quad \text{(2)} \]
Now subtract equation (2) from equation (1): \[ (5x + 8y) - (4.8x + 8y) = 115 - 112 \ 0.2x = 3 \ x = \frac{3}{0.2} = 15 \]
Now substitute \(x = 15\) back into one of the original equations to solve for \(y\). Using \(5x + 8y = 115\): \[ 5(15) + 8y = 115 \ 75 + 8y = 115 \ 8y = 115 - 75 \ 8y = 40 \ y = \frac{40}{8} = 5 \]
So we find \(x = 15\) and \(y = 5\).
Thus, the answer to Question 2 is A: \(x = 15\); \(y = 5\).
In summary, the answers are:
- Question 1: B
- Question 2: A