The equation is .
Since the matrices are equal, the corresponding elements are equal.
\Write two linear equations.
\x + 3y = –22
\2x – y = 19
\Consider the second equation
\2x – y = 19
\Apply addition property of equality: If , then
.
2x – y + y = 19 + y (Add y to each side) \ \
\2x = 19 + y (Apply additive inverse property: – y + y = 0)
\Apply division property of equality: if , then
.
(Divide each side by 2) \ \
(Cancel common terms) \ \
Substitute in x + 3y = – 22.
(Simplify)
Apply multiplication property of equality: if , then
.
(Multiply each side by 2)
(Cancel common terms)
19 + y + 6y = – 44 (Multiply: )
19 + 7y = – 44 (Add: 6y + y = 7y)
Apply subtraction property of equality: if , then
.
19 – 19 + 7y = – 44 – 19 (Subtraction 19 from each side)
\19 – 19 + 7y = – 44 – 19 (Apply additive inverse property: 19 – 19 = 0)
\7y = – 63 (Subtract: – 44 – 19 = – 63)
\Apply division property of equality; if , then
.
(Divide each side by 7)
(Cancel common terms)
y = – 9 (Multiply: )
To find the value of x, substitute – 9 for y in second equation.
\2x + 9 = 19 (Product of two same signs is positive)
\2x + 9 – 9 = 19 – 9 (Subtract 9 from each side)
\2x = 19 – 9 (Apply additive inverse property: 9 – 9 = 0)
\2x = 10 (Subtract: 19 – 9 = 10)
Apply division property of equality; if , then
.
(Divide each side by 2)
(Cancel common terms)
x = 5 (Divide: )
The solution is (5, – 9).