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3 years ago

I estimated that the repairs to my car would cost $80. In fact, they cost $120. What was the percentage error?

Mathematics

1 answer:

Sergio039 [100]3 years ago

5 0

Answer:

69%

Step-by-step explanation:

Im just doing this to get my points up. dont get mad

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Add and simplify <br> 9/10 + 1/9

arlik [135]

Answer:

Step-by-step explanation:

81/90 + 9/81 = 90/90 = 1

3 0

3 years ago

Carter drawers one side of equilateral triangle pqr on the coordinate plane at points P(-3, 2) and Q(5, 2). Which ordered pair i

Neko [114]

Given: Two coordinates of an equilateral triangle P(-3, 2) and Q(5, 2).

To find: Coordinate of third vertex R.

Solution: Let us take coordinate of R is (x,y).

Because we are given PQR is an equilateral triangle, all side of the triangle PQR are equal.

We can say PQ = QR = RS.

Let us find equations by using distance formula.

Distance between two coordinates is given by formula

$Distance = \sqrt{(x2-x1)^2+(y2-y1)^2}$

$PQ=\sqrt{(5-(-3))^2+(2-2)^2} = \sqrt{(5+3)^2+(0)^2} = \sqrt{8^2+0} = \sqrt{64} =8$

$QR=\sqrt{(x-5)^2+(y-2)^2} = \sqrt{x^2-10x+25 + y^2-4y+4} = \sqrt{x^2+y^2-10x-4y+29}$

$RS=\sqrt{(x-(-3)^2+(y-2)^2} = \sqrt{x^2+6x+9 + y^2-4y+4} = \sqrt{x^2+y^2+6x-4y+13}$ .

We know, PQ= QR and PQ= RS.

\sqrt{x^2+y^2-10x-4y+29}[/tex] = 8

Squaring both sides, we get

$x^2+y^2-10x-4y+29 =64$ -------- equation (1)

and \sqrt{x^2+y^2+6x-4y+13}[/tex] = 8

Squaring both sides, we get

$x^2+y^2+6x-4y+13=64$ ---------- equation (2).

Subtracting equation 2 from equation 1.

[/tex]x^2+y^2-10x-4y+29[/tex] = 64

[/tex]x^2+y^2+6x-4y+13[/tex] = 64

----------------------------------------------------

-16x +16 = 0

Subtracting 16 on both sides ,

-16x +16-16 = 0-16

-16x = -16

Dividing -16 on both sides.

-16x/-16 = -16/-16

x=1.

Plugging x=1 in first equation

$(1)^2+y^2-10(1)-4y+29 = 64$

$1+y^2-10-4y+29 = 64$ (Simplifying)

$y^2-4y+20 = 64$

Subtracting 64 from both sides.

$y^2-4y+20-64 = 64-64$

$y^2-4y-44 = 0$

By using quadratic formula..

$y=\frac{-(-4)+\sqrt{(-4)^2-4(1)(-44)} }{2(1)} and$

$y=\frac{-(-4)-\sqrt{(-4)^2-4(1)(-44)} }{2(1)} [tex]y=2\left(1+2\sqrt{3}\right),\:y=2\left(1-2\sqrt{3}\right)$

In decimal form

y=8.928, -4.928.

Therefore, coordinates of vertex R could be (1, 8.928) or (1, -4.928).

7 0

3 years ago

Help me with questions 3 & 4

ASHA 777 [7]

3. -4x - 6

-3(x + 2) - x → ( distribute bracket by - 3)

= - 3x - 6 -x → (collect like terms)

=( - 3x - x) - 6 = - 4x - 6

4. A has the smallest value

A =( 2 - 3 ) = -1

B = 2 × 3 = 6

C = 2 + 3 = 5

D = $\frac{2}{3}$

A is negative while the others are all positive.

Thus A is the smallest value expression

6 0

3 years ago

4 5 6 plz I really need it thanks a lot

Zepler [3.9K]

4. Think about it, it would mean that 4 is the result of 0.4 (40%) multiplied by a number. Therefore, you would divide 4 by 0.4. The answer would be 10.
5. To do this, multiply 0.2 by 700. This gives you 140.
6. Think about it, what percent of 25 is 12. Divide 12 by 25, then multiply by 100 and add a percent sign after it. 12/25 is 0.48. Multiply that by 100 to get 48%.

5 0

3 years ago

Use the expression 28b - 4c. Part B: What is the value of the expression when b = -4 and c = 1? Show your work or explain.

Brilliant_brown [7]

Answer:

The value of the expression is -116

Step-by-step explanation:

Given

$Expression: 28b - 4c$