We first want to isolate the y variable in each equation so we can see what types of functions we are dealing with.
3x-y+4 =0 -> y=3x+4
x^2 - 8y - 1 =0 -> y = 1/8 x^2 - 1/8
now we know we have a positive linear function and a quadratic with a minimum vertex and y intercept at -1/8.
There are a few ways to solve this:
1. Graph the 2 functions to see how many intersection points there are.
A. If you graph both we can see there are 2 intersection points and therefore 2 Real solutions.
2. Since the question is asking about the number of solutions and not the actual solution we need to combine the functions and find the discriminate (d=b^2 - 4ac).
3x+4 = 1/8 x^2 -1/8
8(3x+4) = x^2 - 1
24x + 32 = x^2 - 1
0 = x^2 - 24x - 33
d= (-24)^2 - 4(1)(-33) = 708
since it is a positive value we know there are 2 Real solutions.
7 years ago
Answered By Jesslyn C
We first want to isolate the y variable in each equation so we can see what types of functions we are dealing with.
3x-y+4 =0 -> y=3x+4
x^2 - 8y - 1 =0 -> y = 1/8 x^2 - 1/8
now we know we have a positive linear function and a quadratic with a minimum vertex and y intercept at -1/8.
There are a few ways to solve this:
1. Graph the 2 functions to see how many intersection points there are.
A. If you graph both we can see there are 2 intersection points and therefore 2 Real solutions.
2. Since the question is asking about the number of solutions and not the actual solution we need to combine the functions and find the discriminate (d=b^2 - 4ac).
3x+4 = 1/8 x^2 -1/8
8(3x+4) = x^2 - 1
24x + 32 = x^2 - 1
0 = x^2 - 24x - 33
d= (-24)^2 - 4(1)(-33) = 708
since it is a positive value we know there are 2 Real solutions.