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2 years ago

Detailed answers appreciated: (7a -4) (2a -5)

2 answers:

5 0

Expand the expression?

Perform indicated multiplication:

7a(2a)+7a(-5)-4(2a)-4(-5)

14a^2-35a-8a+20 combine like terms, ie (-35a-8a)=-43a

14a^2-43a+20

lana66690 [7]2 years ago

5 0

1. Us the FOIL method: (a + b)(c + d) = ac + ad + bc + bd:
14a^2 - 35a - 8a + 20
2. Collect like terms:
14a^2 + (-35a - 8a) + 20
3. Simplify:
14a^2 - 43a + 20

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1 4/5 cm by 4 2/5 cm

LenaWriter [7]

If it is area you're looking for, the answer is 7.92 cm^2, or ~7 11/12 cm^2.

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3 years ago

If R is the midpoint of QS, QR= 8x-51 and RS = 3x-6, find QS.

sashaice [31]

QS would be 42. So the way i did it was I:

8x-51=3x-6

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Plugged into both equations of QR and RS to then get the answer of 42

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3 years ago

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4 ^-3 rewrite without an exponent

hichkok12 [17]

Answer:

(1/4)³

Step-by-step explanation:

Hope it helps you

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2 years ago

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f(x) = 3 cos(x) 0 ≤ x ≤ 3π/4 evaluate the Riemann sum with n = 6, taking the sample points to be left endpoints. (Round your ans

Kruka [31]

Answer:

$\int_{0}^{\frac{3 \pi}{4}}3 \cos{\left(x \right)}\ dx\approx 3.099558$

Step-by-step explanation:

We want to find the Riemann sum for $\int_{0}^{\frac{3 \pi}{4}}3 \cos{\left(x \right)}\ dx$ with n = 6, using left endpoints.

The Left Riemann Sum uses the left endpoints of a sub-interval:

$\int_{a}^{b}f(x)dx\approx\Delta{x}\left(f(x_0)+f(x_1)+2f(x_2)+...+f(x_{n-2})+f(x_{n-1})\right)$

where $\Delta{x}=\frac{b-a}{n}$ .

Step 1: Find $\Delta{x}$

We have that $a=0, b=\frac{3\pi }{4}, n=6$

Therefore, $\Delta{x}=\frac{\frac{3 \pi}{4}-0}{6}=\frac{\pi}{8}$

Step 2: Divide the interval $\left[0,\frac{3 \pi}{4}\right]$ into n = 6 sub-intervals of length $\Delta{x}=\frac{\pi}{8}$

$a=\left[0, \frac{\pi}{8}\right], \left[\frac{\pi}{8}, \frac{\pi}{4}\right], \left[\frac{\pi}{4}, \frac{3 \pi}{8}\right], \left[\frac{3 \pi}{8}, \frac{\pi}{2}\right], \left[\frac{\pi}{2}, \frac{5 \pi}{8}\right], \left[\frac{5 \pi}{8}, \frac{3 \pi}{4}\right]=b$

Step 3: Evaluate the function at the left endpoints

$f\left(x_{0}\right)=f(a)=f\left(0\right)=3=3$

$f\left(x_{1}\right)=f\left(\frac{\pi}{8}\right)=3 \sqrt{\frac{\sqrt{2}}{4} + \frac{1}{2}}=2.77163859753386$

$f\left(x_{2}\right)=f\left(\frac{\pi}{4}\right)=\frac{3 \sqrt{2}}{2}=2.12132034355964$

$f\left(x_{3}\right)=f\left(\frac{3 \pi}{8}\right)=3 \sqrt{\frac{1}{2} - \frac{\sqrt{2}}{4}}=1.14805029709527$

$f\left(x_{4}\right)=f\left(\frac{\pi}{2}\right)=0=0$

$f\left(x_{5}\right)=f\left(\frac{5 \pi}{8}\right)=- 3 \sqrt{\frac{1}{2} - \frac{\sqrt{2}}{4}}=-1.14805029709527$

Step 4: Apply the Left Riemann Sum formula

$\frac{\pi}{8}(3+2.77163859753386+2.12132034355964+1.14805029709527+0-1.14805029709527)=3.09955772805315$

$\int_{0}^{\frac{3 \pi}{4}}3 \cos{\left(x \right)}\ dx\approx 3.099558$

5 0

2 years ago

I'll give brainliest

erma4kov [3.2K]

Answer:

I think its D sorry if I get it wrong

Step-by-step explanation:

6 0

3 years ago

Read 2 more answers