McGraw Hill Integrated II, 2012
MH
McGraw Hill Integrated II, 2012 View details
Preparing for Standardized Tests
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Exercise 3 Page 221

Calculate the determinant of the coefficient matrix.

C

Practice makes perfect
Recall that if the determinant of the coefficient matrix is not 0, then the system has a unique solution. Let's rearrange the system and identify the coefficients. 16x-2y=24 12x=3y-36 ⟹ 16x+( -2)y=24 12x+(-3)y=-36We can now write the coefficient matrix of the system. 16& -2 12& -3 Let's find the determinant.
16& -2 12& -3
Calculate determinant

a & b c & d =ad-bc

16(-3)-( -2)( 12)
-48-( -2)( 12)
-48-(-24)
-48+24
-24
The determinant is not 0, so the system of equations has a unique solution. Since the solutions of a system of equations correspond to the common points of the graphs, this means that the graph of this system is two lines with a unique common point. The correct answer is C.