Get expert advice and insights on any topic with IDNLearn.com. Our community provides timely and precise responses to help you understand and solve any issue you face.

Solve each system of equations by using elimination.

[tex]\[
\begin{array}{l}
8p + 8q = 19 \\
5p - 5q = 20
\end{array}
\][/tex]

a. [tex]\((3.19, 0)\)[/tex]
b. [tex]\((3.19, -0.81)\)[/tex]
c. [tex]\((1.57, -0.81)\)[/tex]
d. [tex]\((1.38, 3.19)\)[/tex]


Sagot :

To solve the given system of equations using elimination, follow these steps:

[tex]\[ \begin{array}{l} 8p + 8q = 19 \quad \text{(1)} \\ 5p - 5q = 20 \quad \text{(2)} \end{array} \][/tex]

### Step 1: Align the Coefficients for Elimination

Here, we aim to eliminate one of the variables by aligning coefficients. Let's eliminate [tex]\( q \)[/tex].

### Step 2: Equalize the Coefficients of [tex]\( q \)[/tex]

In order to eliminate [tex]\( q \)[/tex], we need to make the coefficients of [tex]\( q \)[/tex] in both equations opposites. For this, we can multiply equation (1) by 5 and equation (2) by 8:

Multiply equation (1) by 5:
[tex]\[ 5(8p + 8q) = 5 \cdot 19 \\ 40p + 40q = 95 \quad \text{(3)} \][/tex]

Multiply equation (2) by 8:
[tex]\[ 8(5p - 5q) = 8 \cdot 20 \\ 40p - 40q = 160 \quad \text{(4)} \][/tex]

### Step 3: Add or Subtract the Equations to Eliminate [tex]\( q \)[/tex]

Now, add equations (3) and (4) together to eliminate [tex]\( q \)[/tex]:

[tex]\[ (40p + 40q) + (40p - 40q) = 95 + 160 \\ 40p + 40p = 255 \\ 80p = 255 \][/tex]

### Step 4: Solve for [tex]\( p \)[/tex]

[tex]\[ p = \frac{255}{80} \\ p = 3.1875 \approx 3.19 \][/tex]

### Step 5: Substitute [tex]\( p \)[/tex] Back into One of the Original Equations to Solve for [tex]\( q \)[/tex]

Substitute [tex]\( p = 3.19 \)[/tex] into equation (1):
[tex]\[ 8(3.19) + 8q = 19 \\ 25.52 + 8q = 19 \\ 8q = 19 - 25.52 \\ 8q = -6.52 \\ q = \frac{-6.52}{8} \\ q = -0.815 \approx -0.81 \][/tex]

### Conclusion

After solving, we find the solution to be:

[tex]\[ (p, q) = (3.19, -0.81) \][/tex]

None of the options exactly match our found solution of [tex]\((3.19, -0.81)\)[/tex]. This means the system intersects at [tex]\(\boxed{\text{None of the provided options exactly match the intersection point}}.\)[/tex]