Select the best possible first step to solving the system by first eliminating the x variable. 3x + 5y = 1 2x + 4y = −4 Multiply the first equation by 2, and multiply the second equation by 3. Multiply the first equation by −2, and multiply the second equation by 3. Multiply the first equation by −2, and multiply the second equation by −3. None of the above
Mathematics · High School · Mon Jan 18 2021
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Given the equation:
3x + 5y = 1
2x + 4y = -4
Solve the system of linear equation.
Solution:
In order to solve the system of linear equation, we must first solve for x in terms of y in the second equation. To do so, we transpose 4y to the other side and then divide both sides by 2. We must take note that in transposing a number, the sign changes.
2x + 4y = -4
2x = -4y -4
2x/2 = (-4y - 4)/2
x = -2y - 2
Substitute the value of x to the first equations, and solve for y.
3(- 2y - 2) + 5y = 1
-6y - 2 + 5y = 1
-y - 2 = 1
y = -2 -1
y = -3
Substitute the value of y to the formula for x.
x = -2(-3) - 2
x = 6 - 2
x = 4
Final answer:
y = -3
x = 4