The answer is 7x^2 - 2x + 4, so answer D.
Answer:
x = 5
Step-by-step explanation:
4x + 2y + z = 24
2x - 3y - z = 2
5x + y + 2z = 21
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Eliminate z
Add the 1st and 2nd eqn
4x + 2y + z = 24
2x - 3y - z = 2
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6x - 1y = 26 eqn A
Multiply the 2nd eqn by 2, then add the 3rd.
4x - 6y -2z = 4
5x + y + 2z = 21
----------------
9x - 5y = 25 eqn B
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Now you have 2 eqns in 2 unknowns, not 3.
Multiply eqn A by 5 and subtract eqn B.
30x - 5y = 130 eqn A times 5
9x - 5y = 25 eqn B
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21x = 105
x = 5
Answer:
1½ mile
Step-by-step explanation:
Given
3/10 mile = ⅕ hour
Required
Determine the distance in 1 hour
Since rate is constant, we have:
3/10 mile = ⅕ hour
Multiply both sides by 5
5 * 3/10 mile = ⅕ hour * 5
15/10 mile = 5/5 hour
3/2 mile = 1 hour
1½ mile = 1 hour
Hence,the child will walk 1½ mile in 1 hour
Y1 is the simplest parabola. Its vertex is at (0,0) and it passes thru (2,4). This is enough info to conclude that y1 = x^2.
y4, the lower red graph, is a bit more of a challenge. We can easily identify its vertex, which is (-4,0), and several points on the grah, such as (2,-3).
Let's try this: assume that the general equation for a parabola is
y-k = a(x-h)^2, where (h,k) is the vertex. Subst. the known values,
-3-(-4) = a(2-0)^2. Then 1 = a(2)^2, or 1 = 4a, or a = 1/4.
The equation of parabola y4 is y+4 = (1/4)x^2
Or you could elim. the fraction and write the eqn as 4y+16=x^2, or
4y = x^2-16, or y = (1/4)x - 4. Take your pick! Hope this helps you find "a" for the other parabolas.
The best way to find the answer is to solve for x. To start you would add 38 and 39, getting 77, then subtract that from 180 to get the last angle in the triangle, 103. Finally, you would subtract 103 from 180, getting 77, to get x. The only thing you need to do now is to look at all of the answers and figure out which one makes sense for the answer you got. You know it can't be x<77 because it doesn't have the or equal to sign. You know it can't be x>103 because 77 is lower than 103. You know it can't be x<39 because 77 is greater than 39, so the answer has to be x > 38.
