Answer:
She incorrectly multiplied 15 X 1/4
Step-by-step explanation:
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We are asked to evaluate 
.
- The notation |x| denotes absolute value.
The absolute value of a number is its distance from zero.
Absolute value is always positive; distances can't be negative, right?
So we need to find the absolute value of 98, which is:
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Answer:
1) 2x+7
2) -3x+11
3) 0.75x-2
4) -2x+0
5) -1.5x+2
6) -4x+16
Step-by-step explanation:
1) y = mx + c
m = 2 when x=1 , y=9
9 = 2(1)+c
c = 7
y = 2x + 7
2) m = -3
When x=4, y= -1
-1 = -3(4) + c
c = -1+12 = 11
y = -3x + 11
3) m = 0.75
When x= -4, y= -5
-5 = 0.75(-4) + c
-5 = -3 + c
c = -2
y = 0.75x - 2
4) m = (y2-y1)/(x2-x1)
m = (2-(-6))/(-1-3) = 8/-4 = -2
y = -2x + c
When x= -1, y= 2
2 = -2(-1) + c
2 = 2 + c
c = 0
y = -2x + 0
5) m = (-10-(-4))/(8-4)
m = (-10+4)/4 = -6/4 = -1.5
y = -1.5x + c
When x= 4, y= -4
-4 = -1.5(4) + c
-4 = -6 + c
c = 2
y = -1.5x + 2
6) m = (-4-4)/(5-3) = -8/2 = -4
When x= 3, y= 4
4 = -4(3) + c
4 = -12 + c
c = 16
y = -4x + 16
Let's to the first example:
f(x) = x^2 + 9x + 20
Ussing the formula of basckara
a = 1
b = 9
c = 20
Delta = b^2 - 4ac
Delta = 9^2 - 4.(1).(20)
Delta = 81 - 80
Delta = 1
x = [ -b +/- √(Delta) ]/2a
Replacing the data:
x = [ -9 +/- √1 ]/2
x' = (-9 -1)/2 <=> - 5
Or
x" = (-9+1)/2 <=> - 4
_______________
Already the second example:
f(x) = x^2 -4x -60
Ussing the formula of basckara again
a = 1
b = -4
c = -60
Delta = b^2 -4ac
Delta = (-4)^2 -4.(1).(-60)
Delta = 16 + 240
Delta = 256
Then, following:
x = [ -b +/- √(Delta)]/2a
Replacing the information
x = [ -(-4) +/- √256 ]/2
x = [ 4 +/- 16]/2
x' = (4-16)/2 <=> -6
Or
x" = (4+16)/2 <=> 10
______________
Now we are going to the 3 example
x^2 + 24 = 14x
Isolating 14x , but changing the sinal positive to negative
x^2 - 14x + 24 = 0
Now we can to apply the formula of basckara
a = 1
b = -14
c = 24
Delta = b^2 -4ac
Delta = (-14)^2 -4.(1).(24)
Delta = 196 - 96
Delta = 100
Then we stayed with:
x = [ -b +/- √Delta ]/2a
x = [ -(-14) +/- √100 ]/2
We wiil have two possibilities
x' = ( 14 -10)/2 <=> 2
Or
x" = (14 +10)/2 <=> 12
________________
To the last example will be the same thing.
f(x) = x^2 - x -72
a = 1
b = -1
c = -72
Delta = b^2 -4ac
Delta = (-1)^2 -4(1).(-72)
Delta = 1 + 288
Delta = 289
Then we are going to stay:
x = [ -b +/- √Delta]/2a
x = [ -(-1) +/- √289]/2
x = ( 1 +/- 17)/2
We will have two roots
That's :
x = (1 - 17)/2 <=> -8
Or
x = (1+17)/2 <=> 9
Well, this would be your answers.
