Mathematics, 04.12.2019 19:31 emiliabueno38

What are two numbers that multiply to -20 and add up to 1?

Answers: 1

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Answer from: Hazy095

  xy = -20
x + y = 1

x + y = 1
x - x + y = -x + 1
y = -x + 1

xy = -20
x(-x + 1) = -20
  x(-x) + x(1) = -20
-x² + x = 20
-x² + x + 20 = 0
-1(x²) - 1(-x) - 1(-20) = 0
  -1(x² - x - 20) = 0
-1 -1
x² - x - 20 = 0
x = -(-1) ± √((-1)² - 4(1)(-20))
2(1)
x = 1 ± √(1 + 80)
2
x = 1 ± √(81)
2
x = 1 ± 9
2
x = 0.5 ± 4.5
x = 0.5 + 4.5 or x = 0.5 - 4.5
x = 5      or      x = -4

  x + y = 1
  5 + y = 1
- 5 - 5
y = -4
(x, y) = (5, -4)
or
x + y = 1
  -4 + y = 1
+ 4   + 4
y = 5
(x, y) = (-4, 5)

The two numbers that add up to 1 and multiply to -20 are -4 and 5.

Answer from: Quest

he has now walked a total of what?

if i know what this is maybe i can

step-by-step explanation:

Answer from: Quest

d. $180

step-by-step explanation:

if the dimensions of the room is 9ft by 12 ft, we have the area of the floor as,

$a=9\times 12=108\text {ft^2}$

so the area of the floor is 108 square feet, converting that into square yards we get,

$108 \times 0.1111= 12 \text{yd^2}$

the cost of carpet is $15 per square yard, therefore the cost of carpet for 12 square yards is,

$\$15 \times 12=\$180$

hence, the cost of carpet is $180.

assuming the dimensions of the room be,

15 ft by 12 ft

so, the area of the floor of that room is,

$a = 12 \times 15=180\text {ft}^2$

we can convert 180 square feet into square yards, we know that,

1 sq ft = 0.111 sq yard

so, 180 square feet is,

$180 \times 0.111=20 \text {yd}^2$

so the area of floor is 20 square yards.

now, the cost of carpet is 15 dollars per square yard, therefore the cost of carpet for 20 square yards is,

$\$15 \times 20= \$300$

so, it will cost $300.

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