The equations 4 x minus 5 y = 5, 3 x + 10 y = 20, 4 x minus 5 y = negative 5, and 3 x + 10 y = negative 20 are shown on the grap
h below. On a coordinate plane, there are 4 lines. Green line goes through (0, 1) and (2.5, 3). Orange line goes through (0, negative 1) and (2.5, 1). Blue line goes through (0, 2) and (3.5, 1). Pink line goes through (0, negative 2) and (3.5, negative 3). Which system of equations has a solution of approximately (–2.7, –1.2)? 4 x minus 5 y = negative 5 and 3 x + 10 y = negative 20 4 x minus 5 y = 5 and 3 x + 10 y = 20 4 x minus 5 y = 5 and 3 x + 10 y = negative 20 4 x minus 5 y = negative 5 and 3 x + 10 y = 20
2 answers:
Answer:
4 x minus 5 y = negative 5 and 3 x + 10 y = negative 20
Step-by-step explanation:
The equations
4 x - 5 y = 5 (red)
3 x + 10 y = 20 (blue)
4 x - 5 y = -5 (green)
3 x + 10 y = -20 (purple)
are shown in the picture attached. As we can see there, the point (–2.7, –1.2) is on the intersection of the purple and green lines. Therefore is the solution of the system:
4 x - 5 y = -5
3 x + 10 y = -20
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The outline that that illustrate how <em>k</em> values change so that the solutions are the ones in the question are as follows
(a) The number line solution contains zero
Using algebra, we have;
The given quadratic inequality is; -x² + 4 ≥ x + k
The number line solution is the expression of the solution on the number line.
We have;
-x² + 4 ≥ x + k
-x² - x + 4 - k ≥ 0
Dividing by (-1), we get;
x² + x - 4 + k ≤ 0
When - 4 + k = -2
k = 2, we get;
x² + x - 4 + 2 ≤ 0
x² + x - 2 ≤ 0
(x - 1)·(x + 2) ≤ 0
Given that the result of the product is less than zero, we have;
((-3) - 1)·((-3) + 2) > 0
Therefore, the solution are;
x ≤ 1, or x ≥ -2
Which gives
-2 ≤ x ≤ 1
- Using diagram;
The solution of the above inequality includes 0 as shown in the attached number line
- Graphically;
The graph of the inequality is plotted using MS Excel, showing the solution set, of -2 ≤ x ≤ 1
(b) There are no solution to the inequality
In the present case, we have;
((-1)² - 4×(-1) × (4 - k) < 0
17 - 4·k < 0
Let k = 5, we have;
-x² + 4 ≥ x + k
-x² - x + 4 - 5 ≥ 0
-x² - x -1 ≥ 0
The discriminant, is (1² - 4×(-1)×(-1)) = -3 < 0, therefore, there are no real
roots to inequality, and -x² - x -1 is not equal to zero.
- Graphically
Please find attached the graph of the function, which does not intersect with the x-axis, and therefore, has no values at which <em>y</em> = 0
(c) The solution is a single number
-x² + 4 ≥ x + k
When k = x + 5, we have;
0 ≥ x² + 2·x + 1
0 ≥ (x + 1)²
Therefore;
The only solution is; x = -1
Using diagrams:
Please find attached the solution of the function on the number line
- Graphically
The graph of the function showing only one intercept is attached
Learn more here:
Answer:
6 inches
Step-by-step explanation:
Formula for surface area of a cylinder:
Plug in values and solve for the radius:
Divide both sides by
Subtract 90 from both sides
Use the quadratic equation to find the roots
±
(sorry for formatting, Brainly doesn't
allow equations with ± in them)
and
and
and
and
and
and
We can't have a negative radius, so that leaves us with r=6 in.