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2 years ago

1. Consider the system of equations below. What could be the first step in solving by elimination?

Mathematics

1 answer:

leva [86]2 years ago

7 0

Answer:

Multiple the first equation by -1

Step-by-step explanation:

After doing this you add the two equations together and follow the systems of equations as normal

$-3x+-5y=-16\\3x+2y=10\\-3y=-6\\\frac{-3y}{-3} =\frac{-6}{-3} \\y=2$

Therefore y = 2

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60 minutes is 20% of minutes.

PilotLPTM [1.2K]

Answer:

60 minutes is 20% of 300 minutes

Step-by-step explanation:

let x be the number of total minutes

60 = 20% of x

20% = 1/5

60 = 1/5x

multiply both sides by 5

300 = x

x = 300 minutes

8 0

2 years ago

Jason agreed to make 12 payments of $38.50 to buy a new T.V. SO far he has made 8 payment. How much more money does he owe?

alexira [117]

Answer:

154$

Step-by-step explanation:

8 0

2 years ago

3( + 4) + 8 = —3 solve

egoroff_w [7]

3x4 to 12
12+8
Answer 20

5 0

2 years ago

Gwendolyn is asked to solve the equation -43 – 3) = 20. She sh

choli [55]

Answer:

-4x + 12 = 20 is incorrect. she added 12 to 20 instead of subtracting 12 from both sides.

Step-by-step explanation:

It should have been, write problem

-4(x - 3) = 20

Use distributive property.

-4x + 12 = 20

subtract 12 from each side

-4x =8

divide each side by -4

x = -2

4 0

2 years ago

The lifetime of a battery in a certain application is normally distributed with mean μ = 16 hours and standard deviation σ = 2 h

DaniilM [7]

Answer:

Probability that a battery will last more than 19 hours is 0.0668.

Step-by-step explanation:

We are given that the lifetime of a battery in a certain application is normally distributed with mean μ = 16 hours and standard deviation σ = 2 hours.

Let X = lifetime of a battery in a certain application

So, X ~ N( $\mu=16,\sigma^{2} =2^{2}$ )

The z-score probability distribution for normal distribution is given by;

Z = $\frac{ X -\mu}{\sigma}$ ~ N(0,1)

where, $\mu$ = mean lifetime = 16 hours

$\sigma$ = standard deviation = 2 hours

The Z-score measures how many standard deviations the measure is away from the mean. After finding the Z-score, we look at the z-score table and find the p-value (area) associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X.

So, the probability that a battery will last more than 19 hours is given by = P(X > 19 hours)

P(X > 19) = P( $\frac{ X -\mu}{\sigma}$ > $\frac{19-16}{2}$ ) = P(Z > 1.50) = 1 - P(Z $\leq$ 1.50)

= 1 - 0.9332 = 0.0668

Now, in the z table the P(Z $\leq$ x) or P(Z < x) is given. So, the above probability is calculated by looking at the value of x = 1.50 in the z table which has an area of 0.9332.

Hence, the probability that a battery will last more than 19 hours is 0.0668.

5 0

3 years ago