X + y = 12 and y = x - 1. Find the value of 2x + 2y.
2 answers:
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<u>QUESTION 1</u>
The given system of equation is
and
Let us substitute equation (1) into equation (2) to get,
We expand the bracket to get,
We simplify to get.
We group like terms to get
We now substitute in to equation (1) to obtain,
The correct answer is option A.
<u>QUESTION 2</u>
The given system of equations is
and
We make y the subject in equation (2) to get,
We put equation (3) into equation (1) to obtain,
We group like terms to get,
This implies that,
We divide through by to get,
Hence the x-coordinate is
<u>QUESTION 3</u>
The given system is
and
We make the subject in equation (2) to get,
We put equation (3) into equation (1) to obtain,
We expand the bracket to get,
Group like terms to get,
We simplify to get;
This implies that,
Therefore the y-coordinate is 14.