Question

The solution of the system of equations Ax+y=5 and Ax+By=20 is (2,-3). What are the values of A and B

Answer 1

• A = 4
• B = -4

Explanation:

Put the values of x and y in the equations and solve the resulting system.

A(2) +(-3) = 5

A(2) +B(-3) = 20

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The first equation tells the value of A:

2A = 8 . . . . add 3

A = 4 . . . . . .divide by 2

This and the second equation tells the value of B:

(4)(2) -3B = 20

-3B = 12 . . . . . subtract 8

B = -4 . . . . . . . divide by -3

The values of A and B are 4 and -4, respectively.