Injective- (one-to-One)
so
Replace the f(x) with y
10-4x
Interchange the variables
x=10-4y
Solv for y.
y= 5/2 - x/4
So solve for y and replace with f-1 (x).
and it equals
f-1 (x)=5/2- x/4
Answer:
(-1,-1)
Step-by-step explanation:
x=y
2x+3x=-5
x=-1
y=-1
The first equation, 8x - 9y = - 23
Obtain the equation in slope- intercept form
y = mx + c ( m is the slope and c the y-intercept )
to calculate m use the gradient formula
m = ( y₂ - y₁ ) / ( x₂ - x₁ )
with (x₁, y₁ ) = ( 
, 3) and (x₂, y₂ ) = (- 4, - 1 )
m = 
= (- 4)/- 
= 
partial equation is y = x + c
to find c substitute either of the 2 points into the partial equation
using (- 4, - 1 ), then
- 1 = - 
+ c ⇒ c = 
y = x + ← in slope- intercept form
the equation of a line in standard form is
Ax + By = C ( A is a positive integer and B, C are integers )
rearrange the slope- intercept equation into this form
multiply through by 9
9y = 8x + 23 ( subtract 9y and 23 from both sides )
8x - 9y = - 23 in standard form
Answer: B) Infinitely many solutions; both equations are equivalent
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Work Shown:
x+y = 4 ... start with the first equation
x + (-x+4) = 4 ... replace y with (-x+4)
x-x+4 = 4
0x+4 = 4
0+4 = 4
4 = 4 ... this is a true statement regardless of what x you pick
So there are infinitely many solutions. Each solution (x,y) is of the form (x,-x+4). All solutions fall on the line y = -x+4 which is equivalent to x+y = 4. Note how we add x to both sides.
Or you could start with x+y = 4 and subtract x from both sides to get y = -x+4. Either way, we're dealing with the same equation which is why they both graph out the same line.
