<em>Greetings from Brasil...</em>
According to the statement of the question, we can assemble the following system of equation:
X · Y = - 2 i
X + Y = 7 ii
isolating X from i and replacing in ii:
X · Y = - 2
X = - 2/Y
X + Y = 7
(- 2/Y) + Y = 7 <em>multiplying everything by Y</em>
(- 2Y/Y) + Y·Y = 7·Y
- 2 + Y² = 7X <em> rearranging everything</em>
Y² - 7X - 2 = 0 <em>2nd degree equation</em>
Δ = b² - 4·a·c
Δ = (- 7)² - 4·1·(- 2)
Δ = 49 + 8
Δ = 57
X = (- b ± √Δ)/2a
X' = (- (- 7) ± √57)/2·1
X' = (7 + √57)/2
X' = (7 - √57)/2
So, the numbers are:
<h2>
(7 + √57)/2</h2>
and
<h2>
(7 - √57)/2</h2>
9514 1404 393
Answer:
A. subtraction
B. division
C. multiplication
D. addition
Step-by-step explanation:
Observe what is done to the variable. Choose the operation that turns the unwanted value into the appropriate identity element.
A. 3.75 is added. To make that value be 0, we subtract 3.75.
B. -3 is multiplied. To make that value be 1, we divide by -3.
C. m is divided by 5. To make that 1/5 multiplier be 1, we multiply by 5.
D. 4 is subtracted. To make that value be zero, we add 4.
_____
<em>Additional comment</em>
Since subtraction is the same as addition of the opposite, and division is the same as multiplication by the reciprocal, the only two properties we really need are the <em>addition property</em> and <em>multiplication property</em>. Your grader may disagree.
ANSWER: The length of the entire dash is 700 meters.
EXPLANATION:
Because 20% of the dash equals 140 meters, we can use a variable to figure out the length of the entire dash.
Let x be the length of the entire dash.
The length of the entire dash is 700 meters.
