Question

Jorge used a graph to determine a solution to the following system of equations: x + y = 92 and y = 3x – 4 Jorge’s answer is (67, 25). Is he correct? Explain how to check if his solution is correct without using a graph.

Answer 1

his answer isn't correct

Explanation:

we must subtract this equations from each other

x + y = 92

-3x + y = -4

4x = 96

x = 24 "not 67"

then we replace x by the value of it "24"

24 + y = 92

y = 92-24

y = 68 "not 25"

.. ..

Answer 2

Jorge is wrong

Explanation:

We can check if his solution is correct by plugging in the answer into the equations in the system.

x + y = 92

67 + 25 = 92

92 = 92

y = 3x - 4

25 = 3(67) - 4

25
`\\eq` 197

So, Jorge is wrong because his solution makes one of the equations false.