X + y = 20
xy = -3
x + y = 20
x - x + y = -x + 20
y = -x + 20
xy = -3
x(-x + 20) = -3
x(-x) + x(20) = -3
-x² + 20x = -3
-x² + 20x + 3 = 0
-1(x²) - 1(-20x) - 1(-3) = 0
-1(x² - 20x - 3) = 0
-1 -1
x² - 20x - 3 = 0
x = -(-20) ± √((-20)² - 4(1)(-3))
2(1)
x = 20 ± √(400 + 12)
2
x = 20 ± √(412)
2
x = 20 ± 2√(103)
2
x = 10 ± √(103)
x = 10 + √(103) or x = 10 - √(103)
x + y = 20
10 + √(103) + y = 20
- (10 + √(103)) - (10 + √(103))
y = 10 - √(103)
(x, y) = (10 + √(103), 10 - √(103))
or
x + y = 20
10 - √(103) + y = 20
- (10 - √(103)) - (10 - √(103))
y = 10 + √(103)
(x, y) = (10 - √(103), 10 + √(103))
The two numbers that add up to 20 and multiply to -3 are 10 ± √(103).
Answer:
65 cats
Step-by-step explanation:
cats: dogs: total
5: 3: 5+3=8
We need 8 to be 104
104/8 = 13
Multiply each by 13
cats: dogs: total
5*13: 3*13: 8*13
65 39 104
There are 65 cats and 39 dogs
Answer:
113.09734
Step-by-step explanation:
153 pounds; Since 4^4 bricks would be 64, plug it in for b and solve the equation.
25+2(64)
25+128
153