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2 years ago

Multiply. (7x-4)(4x-3)

Mathematics

2 answers:

dlinn [17]2 years ago

7 0

Your answer is 28x^2-37x+12

1) Use the FOIL method: (a+b)(c+d)=ac+ad+bc+bd

28x^2-21x-16x+12

2) Collect like terms

28x^2+(-21-16x)+12

3) Simplify

28x^2-37x+12

Sonbull [250]2 years ago

7 0

Use FOIL

28x-21x-16x+12

-9x+12

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It was estimated that because of people switching to Metro trains about 33000 of CNG 3300 tons of diesel and 21000 tons of petro

Simora [160]

The question is incomplete. Here is the complete question

It was estimated that because of people switching to Metro trains about 33000 of CNG 3300 tons of diesel and 21000 tons of petrol was saved by the end of year 2007 (I) find a fraction of the quantity of diesel saved to the quantity of petrol saved (ii) find the quantity of cng to the quantity of diesel saved

Answer:

(I) 11/70

(II) 1/10

Step-by-step explanation:

Metro trains contain 330,000 tons of CNG

3300 tons of diesel was saved

21000 tons of petrol was saved at the end of 2007

(I) The fraction of the quantity of diesel saved to the quantity of petrol saved can be calculated as follows

= 3300/21000

= 11/70

(II) The fraction of the quantity of CNG saved to the quantity of diesel can be calculated as follows

= 3300/33000

= 1/10

5 0

3 years ago

Calculus 3 help please.

Reptile [31]

I assume each path $C$ is oriented positively/counterclockwise.

(a) Parameterize $C$ by

$\begin{cases} x(t) = 4\cos(t) \\ y(t) = 4\sin(t)\end{cases} \implies \begin{cases} x'(t) = -4\sin(t) \\ y'(t) = 4\cos(t) \end{cases}$

with $-\frac\pi2\le t\le\frac\pi2$ . Then the line element is

$ds = \sqrt{x'(t)^2 + y'(t)^2} \, dt = \sqrt{16(\sin^2(t)+\cos^2(t))} \, dt = 4\,dt$

and the integral reduces to

$\displaystyle \int_C xy^4 \, ds = \int_{-\pi/2}^{\pi/2} (4\cos(t)) (4\sin(t))^4 (4\,dt) = 4^6 \int_{-\pi/2}^{\pi/2} \cos(t) \sin^4(t) \, dt$

The integrand is symmetric about $t=0$ , so

$\displaystyle 4^6 \int_{-\pi/2}^{\pi/2} \cos(t) \sin^4(t) \, dt = 2^{13} \int_0^{\pi/2} \cos(t) \sin^4(t) \,dt$

Substitute $u=\sin(t)$ and $du=\cos(t)\,dt$ . Then we get

$\displaystyle 2^{13} \int_0^{\pi/2} \cos(t) \sin^4(t) \, dt = 2^{13} \int_0^1 u^4 \, du = \frac{2^{13}}5 (1^5 - 0^5) = \boxed{\frac{8192}5}$

(b) Parameterize $C$ by

$\begin{cases} x(t) = 2(1-t) + 5t = 3t - 2 \\ y(t) = 0(1-t) + 4t = 4t \end{cases} \implies \begin{cases} x'(t) = 3 \\ y'(t) = 4 \end{cases}$

with $0\le t\le1$ . Then

$ds = \sqrt{3^2+4^2} \, dt = 5\,dt$

and

$\displaystyle \int_C x e^y \, ds = \int_0^1 (3t-2) e^{4t} (5\,dt) = 5 \int_0^1 (3t - 2) e^{4t} \, dt$

Integrate by parts with

$u = 3t-2 \implies du = 3\,dt \\\\ dv = e^{4t} \, dt \implies v = \frac14 e^{4t}$

$\displaystyle \int u\,dv = uv - \int v\,du$

$\implies \displaystyle 5 \int_0^1 (3t-2) e^{4t} \,dt = \frac54 (3t-2) e^{4t} \bigg|_{t=0}^{t=1} - \frac{15}4 \int_0^1 e^{4t} \,dt \\\\ ~~~~~~~~ = \frac54 (e^4 + 2) - \frac{15}{16} e^{4t} \bigg|_{t=0}^{t=1} \\\\ ~~~~~~~~ = \frac54 (e^4 + 2) - \frac{15}{16} (e^4 - 1) = \boxed{\frac{5e^4 + 55}{16}}$

$\begin{cases} x(t) = 3(1-t)+t = -2t+3 \\ y(t) = (1-t)+2t = t+1 \\ z(t) = 2(1-t)+5t = 3t+2 \end{cases} \implies \begin{cases} x'(t) = -2 \\ y'(t) = 1 \\ z'(t) = 3 \end{cases}$

with $0\le t\le1$ . Then

$ds = \sqrt{(-2)^2 + 1^2 + 3^2} \, dt = \sqrt{14} \, dt$

and

$\displaystyle \int_C y^2 z \, ds = \int_0^1 (t+1)^2 (3t+2) \left(\sqrt{14}\,ds\right) \\\\ ~~~~~~~~ = \sqrt{14} \int_0^1 \left(3t^3 + 8t^2 + 7t + 2\right) \, dt \\\\ ~~~~~~~~ = \sqrt{14} \left(\frac34 t^4 + \frac83 t^3 + \frac72 t^2 + 2t\right) \bigg|_{t=0}^{t=1} \\\\ ~~~~~~~~ = \sqrt{14} \left(\frac34 + \frac83 + \frac72 + 2\right) = \boxed{\frac{107\sqrt{14}}{12}}$

8 0

1 year ago

HRLP ME PLEASE BRO PLEASE ALL I NEED IS THE ANSWER

earnstyle [38]

Answer:
It’s the first one

6 0

2 years ago

If a man goes to a cafe he wants to buy a wrap with the price of 8.80 dollars he gives the cafe lady 10 dollars how much change

Tomtit [17]

It would be $1.20
8.80 + 1.20 = 10

3 0

2 years ago

Find the roots of f(x)=x^2+10x−96

a_sh-v [17]

Answer:

x = -16 or x = 6

Step-by-step explanation:

To find the roots of a polynomial function, set the polynomial equal to zero and solve for x.

x² + 10x - 96 = 0

We need to factor the left side. The left side is a quadratic polynomial whose first coefficient is 1. We need two numbers whose product is -96 and whose sum is 10. The numbers are 16 and -6.

(x + 16)(x - 6) = 0

If a product of two factors equals zero, then one factor or the other or both must equal zero.

x + 16 = 0 or x - 6 = 0

x = -16 or x = 6

6 0

3 years ago