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2 years ago

3x - 2y + 3z = -20 4x - 3y - 2z = 7 -5x + 5y + z = 9

Mathematics

1 answer:

skelet666 [1.2K]2 years ago

8 0

Answer:

x= 4 y= 7 z= -6

Step-by-step explanation:

solve for one and you get them all

First, I got rid of the z by multiplying common factors (multiplied z by 2) and added equations 2 and 3 together after multiplying by 2

4x - 3y - 2z = 7

-10x+10y+2z= 18

-6x+7y= 25

Then multiplied z by -3 (to get rid of the z) with the original equation 3

3x - 2y + 3z = -20

15x-15y-3z= -27

18x-17y= -47

Next find common thing between the 2 equations we got and multiply it by that and combine (we can multiply first equation by 3 to get rid of the x and solve for y)

-18x+21y= 75

18x-17y= -47

y=7

Work backwards, substitute 7 into the above equation, you get x= 4 and then same for z to get z= -6

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The number of teams who entered in a 3-on-3 charity basketball tournament can be modeled by function T, where x is the number of

Svetradugi [14.3K]

Answer:

<u>Option A:</u>

$R(x)=20x^2+300x+1080$

Explanation:

The revenue, R(x) is the product of the number of teams who entered the tournament, T(x), times the entry fee paid by each team, F(x); then you can write:

$R(x)=T(x)\times F(x)$

Thus you must multiply the two functions (polynomials):

$R(x)=(4x+24)\times (5x+45)$

Use distributive property:

$R(x)=(4x+24)\times (5x+45)=(4x)(5x)+(4x)(45)+(24)(5x)+(24)(45)$

Simplify:

$R(x)=(4x)(5x)+(4x)(45)+(24)(5x)+(24)(45)=20x^2+180x+120x+1080$

Add like terms:

$R(x)=20x^2+180x+120x+1080=20x^2+300x+1080$

3 0

3 years ago

Strontium-90 has a half-life of 28.8 years. If you start with a 300-gram sample of strontium-90,

Kazeer [188]

Answer: 2.66 × 10⁻¹³

<u>Step-by-step explanation:</u>

First, use the decay formula $A=A_oe^{kt}$ where

A is the final amount (amount left)
A₀ is the initial amount (amount you started with)
k is the rate of decay (you need to solve for this)
t is the time

Given:

A = 1/2(300) = 150
A₀ = 300
k = unknown
t = 28.8

$150=300e^{28.8k}\\\\0.5=e^{28.8k}\\\\ln(0.5)=ln(e^{28.8k})\\\\ln(0.5)=28.8k\\\\\\\dfrac{ln(0.5)}{28.8}=k\\\\\\\large\boxed{-0.0240676=k}\\$

Next, input the k-value and the new t-value to solve for A.

A = unknown
A₀ = 300
k = -0.0240676
t = 1440

$A=300e^{1440(-.0240676)}\\\\\large\boxed{A=2.66\times 10^{-13}}\\$

5 0

3 years ago

Help me asap! I will give you marks

Law Incorporation [45]

Recall the binomial theorem.

$(a+b)^n = \displaystyle \sum_{k=0}^n \binom nk a^{n-k} b^k$

1. The binomial expansion of $\left(1+\frac x3\right)^7$ is

$\left(1 + \dfrac x3\right)^7 = \displaystyle\sum_{k=0}^7 \binom 7k 1^{7-k} \left(\frac x3\right)^k = \sum_{k=0}^7 \binom 7k \frac{x^k}{3^k}$

Observe that

$k = 1 \implies \dbinom 71 \left(\dfrac x3\right)^1 = \dfrac73 x$

$k = 2 \implies \dbinom 72 \left(\dfrac x3\right)^2 = \dfrac73 x^2$

When we multiply these by $8-9x$ ,

• $8$ and $\frac73 x^2$ combine to make $\frac{56}3 x^2$

• $-9x$ and $\frac73 x$ combine to make $-\frac{63}3 x^2 = -21x^2$

and the sum of these terms is

$\dfrac{56}3 x^2 - 21x^2 = \boxed{-\dfrac73 x^2}$

2. The binomial expansion is

$\left(2a - \dfrac b2\right)^8 = \displaystyle \sum_{k=0}^8 \binom 8k (2a)^{8-k} \left(-\frac b2\right)^k = \sum_{k=0}^8 \binom 8k 2^{8-2k} a^{8-k} b^k$