Question
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Solve the system of linear equations shown below. \( 2 a-3 b=18 \) \( 5 a+2 b=7 \) Fill in the blanks to write the solution in the form (a,b)

Ask by Medina Coleman. in the United States
Jan 27,2025

Real Tutor Solution

Tutor-Verified Answer

Answer

The solution is \( (3, -4) \).

Solution

To solve the system of linear equations: \[ \begin{cases} 2a - 3b = 18 \quad \text{(1)} \\ 5a + 2b = 7 \quad \text{(2)} \end{cases} \] **Step 1: Eliminate one variable** Let's eliminate \( b \) by making the coefficients of \( b \) in both equations opposites. - Multiply equation (1) by 2: \[ 4a - 6b = 36 \quad \text{(3)} \] - Multiply equation (2) by 3: \[ 15a + 6b = 21 \quad \text{(4)} \] **Step 2: Add equations (3) and (4)** \[ (4a - 6b) + (15a + 6b) = 36 + 21 \] \[ 19a = 57 \] \[ a = \frac{57}{19} = 3 \] **Step 3: Substitute \( a = 3 \) into one of the original equations to find \( b \)** Using equation (1): \[ 2(3) - 3b = 18 \] \[ 6 - 3b = 18 \] \[ -3b = 12 \] \[ b = -4 \] **Solution:** \[ (a, b) = (3, -4) \] **Answer:** \((3,-4)\)

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Bonus Knowledge

To solve the system of equations, we can use the substitution or elimination method. Let's use the elimination method here. First, we can multiply the first equation by 2 to align the coefficients of \( b \): 1. \( 4a - 6b = 36 \) (after multiplying the first equation by 2) 2. \( 5a + 2b = 7 \) Now, we can multiply the second equation by 3 to eliminate \( b \) later: 1. \( 4a - 6b = 36 \) 2. \( 15a + 6b = 21 \) (after multiplying the second equation by 3) Next, we add the two equations: \[ (4a - 6b) + (15a + 6b) = 36 + 21 \] This simplifies to: \[ 19a = 57 \] Now, solve for \( a \): \[ a = \frac{57}{19} = 3 \] Now, substitute \( a = 3 \) back into one of the original equations to find \( b \). Let's use the first equation: \[ 2(3) - 3b = 18 \] This simplifies to: \[ 6 - 3b = 18 \] Now, solve for \( b \): \[ -3b = 18 - 6 \Rightarrow -3b = 12 \Rightarrow b = -4 \] Thus, the solution in the form \( (a,b) \) is \( (3, -4) \).

Related Questions

7. Efectueaza sis scrie rezultatul sub formă de putere: \( \begin{array}{lll}\text { a) } \frac{18}{5} \cdot\left(\frac{18}{5}\right)^{2}= & \text { b) }\left(\frac{6}{5}\right)^{2} \cdot\left(\frac{6}{5}\right)^{3} \cdot \frac{6}{5}= & \text { c) }\left(\frac{19}{5}\right)^{5} \cdot\left(\frac{19}{5}\right)^{16}= \\ \begin{array}{lll}\text { d) } \frac{3}{2} \cdot\left(\frac{3}{2}\right)^{3} \cdot\left(\frac{3}{2}\right)^{0} \cdot\left(\frac{3}{2}\right)^{4}= & \text { e) }\left[\left(\frac{28}{5}\right)^{2}\right]^{3}= & \text { f) }\left[\left(\frac{5}{6}\right)^{6}\right]^{7}= \\ \text { g) }\left[\left(\frac{24}{5}\right)^{2} \cdot\left(\frac{24}{5}\right)^{3}\right]^{8}= & \text { h) }\left[\frac{5}{7} \cdot\left(\frac{5}{7}\right)^{0} \cdot\left(\frac{5}{7}\right)^{4}\right]^{5}= & \text { i) }\left(\frac{29}{10}\right)^{10}:\left(\frac{29}{10}\right)^{7}=\end{array} \\ \left.\left.\begin{array}{lll}\text { j) }\left(\frac{1}{3}\right)^{17}: \frac{1}{3}= & \left.\text { k) }\left(\frac{3}{7}\right)^{11} \cdot\left(\frac{9}{49}\right)^{3}:\left(\frac{3}{7}\right)^{15}=1\right)\end{array}\right]\left(1 \frac{1}{2}\right)^{2}\right]^{8}:\left(\frac{3}{2}\right)^{13}= \\ \text { m) }\left(\frac{9}{10}\right)^{7} \cdot\left(\frac{1}{5}\right)^{7}= & \text { n) }\left(\frac{5}{2}\right)^{10} \cdot\left(\frac{8}{5}\right)^{10}: 2^{10}= & \text { o) } 9^{3} \cdot\left(\frac{7}{10}\right)^{3}:\left(\frac{63}{10}\right)^{3}= \\ \text { p) }\left[\left(\frac{1}{5}\right)^{7}\right]^{2} \cdot 6^{14}:\left(\frac{6}{5}\right)^{14}= & \text { q) }\left(\frac{5}{2}\right)^{7}:\left(\frac{5}{2}\right)^{5}= & \end{array} \)
Algebra Romania Jan 30, 2025

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