<PRE><B>Question 963864</B>
{8x+3y=5. And. 4x-3y= 7} 
Let D be the determinant with all the variables, Dx be the determinant for x and Dy be the determinant for y, then
D = matrix(row 1 is 8 3, row 2 is 4 -3) = -24 -12 = -36
Dx = matrix(row 1 is 5  3, row 2 is 7  -3) = -15 -21 = -36
Dy = matrix(row 1 is 8  5, row 2 is 4  7) = 56 -20 = 36
x = Dx / D = -36 / -36 = 1
y = Dy / D = 36 / -36 = -1
therefore,
x = 1, y = -1
check the answer by substituting for x and y in the given equations
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8(1) +3(-1) = 5
8 -3 = 5
5 = 5
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4(1) -3(-1) = 7
4 +3 = 7
7 = 7
our answer checks
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