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solve matrix 4x-7y=2 and 3x+5y=9

0 votes
please write a matrix equation for the system of equation

and if you want help me with this one 2a+3b-5c=1, 7a+3c=7  and 3a-6b+c=-5

~thank you so much.
asked Mar 6, 2014 in ALGEBRA 2 by mathgirl Apprentice

2 Answers

0 votes

Given equations are 4x-7y = 2 ---> (1)

3x+5y = 9 ---> (2)

Convert the above equations in to matrix form.

We solve the equations in cramer's method.

AX = B

A is coefficient matrix, B is constant matrix and X is variable matrix.

image

image

DetA = 20+21 = 41

image

image= 10+63 = 73

image

image = 36-6 = 30

image

Solution x = 73/41 and y = 30/41.

answered Mar 6, 2014 by david Expert
0 votes

Given equations are 2a+3b-5c = 1 ---> (1)

7a+3c = 7 ---> (2)

3a-6b+c = -5 ---> (3)

Convert the above equations in to matrix form.

We solve the equations in cramer's method.

AX = B

A is coefficient matrix, B is constant matrix and X is variable matrix.

image

image

= 2(0+18)-3(7-9)-5(-42-0)

= 36+6+210 = 252

image

image1(0+18)-3(7+15)-5(-42+0)

= 18-66+210 = 162

image

image2(7+15)-1(7-9)-5(-35-21)

= 44+2+280 = 326

image

image2(0+42)-3(-35-21)+1(-42-0)

= 84+168-42 = 210

image

a = 162/252, b = 326/252, c = 210/252

Solution a = 81/126, b = 163/126, c = 105/126.

answered Mar 6, 2014 by david Expert

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