3x + y = 8. -x - 2y = -10
Mathematics · College · Sun Jan 24 2021
Answered on
Given the systems of linear equation:
3x + y = 8
-x - 2y = -10
Solution:
We can solve for the value of x by doing the substitution method, whereas, we choose one equation and solve for the value of y, then substitute it to the other equation. For the equation that' we'll solve for y, we'll choose the first equation.
3x + y = 8
Transpose 3x on the other side of the equation, hence it must be taken to note that in transposing a number, the sign changes.
y = 8 - 3x
Substitute the value of y to the second equation.
-x - 2(8 - 3x) = -10
-x - 16 - 6x = -10
-7x - 16 = -10
Transpose -16 on the other side of the equation, hence it must be taken to note that in transposing a number, the sign changes.
-7x = -10 + 16
-7x = 6
Divide both sides by -7 in order to cancel out -7x.
-7x/-7 = 6/-7
x = -6/7
Final answer:
x = -6.7