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A student worked out the following problem to find
the solution of the system:
y=x^2+3x-5
y=4x+1
Here is the work the student did:
y=x^2+3x-5
y=4x+1
x^2+3x-5=4x+1
x^2-x-6=0
(x-3)(x+2)=0
x=3 and x=-2
The equations intersect at (−2, 0)???????????? (3, 0).
Is the student correct? If not, explain why and find the
correct solutions.

Respuesta :

calculista
we have that

y=x²+3x-5
y=4x+1

using a graph tool
see the attached figure

the solution are the points
(-2,-7)
(3,13)

the solution obtained by the student
(-2,0)
(3,0)
is incorrect because the values ​​of the coordinate y are incorrect
the values of x are correct
x1=-2
x2=3

with those values ​​of x obtained, the student had to substitute it in any of the two equations to obtain the value of y
so
for x=3
y=4x+1------> 4*(3)+1-----> y=13

for x=-2
y=4x+1------> 4*(-2)+1-----> y=-7

Ver imagen calculista

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