7x + 8y = -18 9x + 4y = 2
1 answer:
Answer:
(x, y) = (2, -4)
Step-by-step explanation:
No question is posed, and no solution method is specified. We presume you're interested in the values of x and y that make both equations true.
<h3>Solution</h3>A quick and easy way to find the solution of two linear equations is to type them into a graphing calculator. The result is shown in the attachment.
The solution is the point that satisfies both equations, their point of intersection. The solution is (x, y) = (2, -4).
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<em>Additional comment</em>
We note that the y-coefficients are related by a factor of 2, and the other coefficients of the second equation are larger than those of the first equation. This suggests using "elimination" or "linear combination" to solve the equations by eliminating the y-variable.
Subtracting the first equation from twice the second gives ...
2(9x +4y) -(7x +8y) = 2(2) -(-18)
11x = 22 . . . . . . . simplify
x = 2 . . . . . . . . divide by 11
Substituting for x in the second equation gives ...
9(2) +4y = 2
4y = -16 . . . . . . . . subtract 18
y = -4 . . . . . . . divide by 4
The solution is (x, y) = (2, -4).
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