Answer:
Step-by-step explanation:
To find the value of x, Cramer's rule says you replace the x-coefficients with the equation constants to form the matrix whose determinant is the numerator of the fraction. The denominator is the determinant of the matrix of coefficients. The equation constants are 148 and 246, so you expect to find those in the first column of the numerator (answer choices A and C).
The calculation is carried out correctly only in answer choice A.
Answer:
$337.50
Step-by-step explanation:
The computation of the number of miles need to drive for determining the same cost is given below:
Let us assume the miles be x
So for the first plan, the equation is
= $0.90x
And for the second plan, the equation is
= $75 + $0.70x
Now equate this
0.90x = $75 + 0.70x
0.90x - 0.70x = $75
0.20x = $75
x = $75 ÷ 0.20
= 375 miles
Now the same cost would be
For plan A and plan B
0.90x = $75 + 0.70x
0.90(375) = $75 + 0.70(375)
$337.5 = $75 + $262.50
$337.50 = $337.50
Where's the so-called "parabola tool?"
The vertex is relatively easy to find. Find the midpoint of the segment of the x-axis connecting x=2 and x=6; it is x=4. Then evaluate the function at x=4:
f(4) = (4-2)(4-6) = 2(-2) = -4. The vertex is at (4,-4).
Plot (4,-4). Then (arbitrarily) let x=0 and find y: f(0) = y = (-2)(-6) = -12.
So, when x = 0, y = -12.
Plot this point (1, -12). realize that the parabola is symmetric about the line x=4. (1,-12) is 3 units to the left of the axis of symm, and thus another point on the parab. is 3 units to the right of this axis, x= 7. Plot (7,-12). Now draw the parabola thru (7,-12), (1, -12) and (4, -4). The parab. opens up.
C. {-2,2,3,4}
this is the answer
