Answer:
stop cheating on your tests
Step-by-step explanation:
Brainly is not meant for cheating
<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>
Answer:
z = -5
Step-by-step explanation:
3(0.7z + 2.8) = 7(1.5z + 7.2)
2.1z + 8.4 = 10.5z + 50.4
2.1z - 10.5z = 50.4 - 8.4
-8.4z = 42
z = 42/(-8.4)
z = -5
Answer:
24.30 Difference, sale price 56.70
Step-by-step explanation:
30% off 81.00 is 56.70
The difference is 24.30
