Use the substitution method:
[tex]\[
\begin{array}{l}
\frac{1}{2} x+\frac{1}{2} y=2 \cdot 5 \\
\frac{2}{5} x+y=3 \cdot 5
\end{array}
\][/tex]



Answer :

Of course! Let's solve the system of equations using the substitution method step-by-step.

We have the system:

[tex]\[ \begin{cases} \frac{1}{2}x + \frac{1}{2}y = 2 \cdot 5 \quad \text{(Equation 1)} \\ \frac{2}{5}x + y = 3 \cdot 5 \quad \text{(Equation 2)} \end{cases} \][/tex]

First, simplify both equations by multiplying through by constants to clear the fractions.

Equation 1:
[tex]\[ \frac{1}{2}x + \frac{1}{2}y = 10 \Rightarrow x + y = 20 \quad \text{(1)} \][/tex]

Equation 2:
[tex]\[ \frac{2}{5}x + y = 15 \Rightarrow 2x + 5y = 75 \quad \text{(2)} \][/tex]

Now, solve Equation (1) for [tex]\(y\)[/tex]:

[tex]\[ x + y = 20 \Rightarrow y = 20 - x \quad \text{(3)} \][/tex]

Substitute [tex]\(y = 20 - x\)[/tex] from Equation (3) into Equation (2):

[tex]\[ 2x + 5(20 - x) = 75 \][/tex]

Distribute and simplify:

[tex]\[ 2x + 100 - 5x = 75 \Rightarrow -3x + 100 = 75 \][/tex]

Isolate [tex]\(x\)[/tex]:

[tex]\[ -3x = 75 - 100 \Rightarrow -3x = -25 \Rightarrow x = \frac{-25}{-3} = \frac{25}{3} = 8.333\ldots \approx 8.333 \][/tex]

Now, substitute [tex]\(x = \frac{25}{3}\)[/tex] back into Equation (3) to find [tex]\(y\)[/tex]:

[tex]\[ y = 20 - \frac{25}{3} \][/tex]

Convert 20 to a fraction with denominator 3:

[tex]\[ y = \frac{60}{3} - \frac{25}{3} = \frac{60 - 25}{3} = \frac{35}{3} = 11.666\ldots \approx 11.667 \][/tex]

So, the solution to the system of equations is:

[tex]\[ \left( \frac{25}{3}, \frac{35}{3} \right) \approx (8.333, 11.667) \][/tex]

Thus, the values of [tex]\(x\)[/tex] and [tex]\(y\)[/tex] are approximately:

[tex]\[ x \approx 8.333, \quad y \approx 11.667 \][/tex]