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3 years ago

What score does he need

Mathematics

2 answers:

matrenka [14]3 years ago

8 0

(90+73+60+x)/4=75
Multiple both sides by 4
90+73+60+x=300
223+x=300
x=77

kykrilka [37]3 years ago

3 0

The score he needs is a 77

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Find the value of m if 13m + 24m = 41m

grigory [225]

Answer:

m=0

Step-by-step explanation:

Add

13m

and

24m

.37

41m

Move all terms containing m

to the left side of the equation.

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2 years ago

Maisie has saved up $50 to buy concert tickets, but the tickets cost $125. She is able to earn $15 per day by walking her neighb

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Subtract 50 from 125

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If Maisie walks her neighbors dogs for 5 days, she will save up to a total of 125

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4 years ago

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Find the vertex of f(x) = 3(x-7)(x+5)

Inessa05 [86]

Answer:

The vertex is at (1, -108).

Step-by-step explanation:

We have the function:

$f(x)=3(x-7)(x+5)$

And we want to find its vertex point.

Note that this is in factored form. Hence, our roots/zeros are x = 7 and x = -5.

Since a parabola is symmetric along its vertex, the x-coordinate of the vertex is halfway between the two zeros. Hence:

$\displaystyle x=\frac{7+(-5)}{2}=\frac{2}{2}=1$

To find the y-coordinate, substitute this back into the function. Hence:

$f(1)=3((1)-7)((1)+5)=3(-6)(6)=-108$

Therefore, our vertex is at (1, -108).

4 0

3 years ago

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A month of the year is chosen at random. What is the probability that the month starts with the letter J or the letter M?

ryzh [129]

Answer:

5/12

Step-by-step explanation:

the the ones that can be choosing are January March May June and July.

7 0

3 years ago

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Please verify the following trigonometric identities.

Nina [5.8K]

Seems like there is a correction in the first question (RHS is tanx.tany)

(i) For convenience: let tanx = a ; tany = b

Thus, tanx + tany = a + b

Moreover, cotx = 1/tanx = 1/a ; coty = 1/b

Thus,

cotx + coty = 1/a + 1/b = (a + b)/ab

Hence,

=> (tanx + tany)/(cotx + coty)

=> (a + b) / { (a + b)/ab }

=> ab(a + b)/(a + b)

=> ab => tanx.tany , proved.

(ii) For convenience: let sinx = a ; cosx = b

As we know, sin²x + cos²x = 1 => a²+b²=1

=> (a³ + b³)/(a + b)

=> (a + b)(a² + b² - ab) / (a + b)

=> (a² + b² - ab)

=> 1 - ab => 1 - sinx.cosx , proved

(iii): let x/2 = A

=> tan(x/2) + cosx.tan(x/2)

=> tanA + cos2A.tanA

=> tanA [1 + cos2A]

=> tanA (2cos²A) {1+cos2A = 2cos²A}

=> (sinA/cosA) (2cos²A)

=> sinA (2cosA)

=> 2sinAcosA

=> sin2A

=> sin2(x/2)

=> sinx proved

Letting x/2 = A is not mandatory. I did it to decease words*(in a line).

Indentities used:

• sin²A + cos²A = 1

• (a³ + b³) = (a + b)(a² + b² - 1)

• 1 + cosA = 2 cos²(A/2)

• tanA = sinA/cosA.

• 2sinAcosA = sin2A

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