1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
gogolik [260]
3 years ago
7

How do I solve system of equations substitution method??!!?!???

Mathematics
1 answer:
adelina 88 [10]3 years ago
8 0
For example:

x+2y=7
6x+7y=2
__________

x=7-2y *
6*(7-2y)+7y=2 **

__________

x=7-2y
42-12y+7y=2
__________

x=7-2y
-5y=-40
__________

x=7-2y
y=8

x=-9
You might be interested in
Can anyone help me on this problem? Please it doesn’t make sense to me...
Sav [38]

Answer:

6

Step-by-step explanation:

Cost per item is found by dividing the cost by the number of items. If the woman bought n items for $120, the cost of each item is $120/n. If the woman bought 24 more items, n+24, at the same price, then the cost per item is $120/(n+24). The problem statement tells us this last cost is $16 less than the first cost:

120/(n+24) = (120/n) -16

Multiplying by n(n+24) gives ...

120n = 120(n+24) -16(n)(n+24)

0 = 120·24 -16n^2 -16·24n . . . . . . subtract 120n and collect terms

n^2 +24n -180 = 0 . . . . . . . . . . . . . divide by -16 to make the numbers smaller

(n +30)(n -6) = 0 . . . . . . . . . . . . . . factor the quadratic

The solutions to this are the values of n that make the factors zero: n = -30, n = 6. The negative value of n has no meaning in this context, so n=6 is the solution to the equation.

The woman bought 6 items.

_____

Check

When the woman bought 6 items for $120, she paid $120/6 = $20 for each of them. If she bought 6+24 = 30 items for the same money, she would pay $120/30 = $4 for each item. That amount, $4, is $16 less than the $20 she paid for each item.

3 0
3 years ago
I need help with number 4
Stella [2.4K]
The answer would be A 4.2x3.7
7 0
3 years ago
According to the Guinness Book of World Records, a woman from Russia, Mrs. Vassilyeva, had 69 children between the years 1725 to
Maurinko [17]

Answer:

36.36% probability that she gave birth to quadruplets

Step-by-step explanation:

A probability is the number of desired outcomes divided by the number of total outcoes.

Desired outcomes:

Giving births to quadruplets.

She has 4 sets of quadruplets.

So D = 4

Total outcomes:

At least 3 children(triplets).

7 sets of triplets and 4 sets of quadruplets.

So T = 7 + 4 = 11

Probability:

p = \frac{D}{T} = \frac{4}{11} = 0.3636

36.36% probability that she gave birth to quadruplets

8 0
3 years ago
The mean length of 4 childrens' big finger is 14cm. The mean length of 9 adults' big finger is 16.1cm. What is the mean length (
Mamont248 [21]

Answer:

The mean length of the 13 people's big finger is 15.45 cm

Step-by-step explanation:

Given;

mean length of 4 childrens' big finger, x' = 14cm

mean length of 9 adults' big finger is 16.1cm, x'' = 16.1cm

Let the total length of the 4 childrens' big finger = t

x' = \frac{t}{n} \\\\x' = \frac{t}{4}\\\\t = 4x'\\\\t = 4 *14\\\\t = 56 \ cm

Let the total length of the 9 adults' big finger = T

x'' = \frac{T}{N} \\\\x'' = \frac{T}{9}\\\\T = 9x''\\\\T = 9*16.1\\\\T = 144.9 \ cm

The total length of the 13 people's big finger = t + T

                                                                           = 56 + 144.9

                                                                            =200.9 cm

The mean length of these 13 people's big finger;

x''' = (200.9) / 13

x''' = 15.4539 cm

x''' = 15.45 cm (2 DP)

Therefore, the mean length of the 13 people's big finger is 15.45 cm

3 0
3 years ago
Roll a 1-6 number cube twice. Probability of a<br> 6 both times
avanturin [10]
1/36 because there are 6 sides and the you are trying to figure out what the probiblity of rolling 1 out of 6 is
8 0
3 years ago
Other questions:
  • A digit in the hundredths place has ten times the value of the same digit in the thousands place
    8·1 answer
  • PLEASE ANSWER QUICKLY GUYS I'M OFFERING 10PTS (Wayy more than what it's worth) AND BRAINLIEST ANSWER. THANKS IN ADVANCE, I GREAT
    11·2 answers
  • The area of a regular octagon is 25 square cm . What is the area of a regular octagon with sides five times as large as the side
    10·1 answer
  • Which line appears to have the same slope as the equation x-y=4 and has a y-intercept that is 2 units above the y-intercept of t
    11·1 answer
  • 15=3-(z+6) solve the equation and check your solution
    10·2 answers
  • In circle O below, what is the value of f ?
    11·1 answer
  • A number cube is rolled 24 times and lands on 2 four times and on 6 three times. a. Find the experimental probability of landing
    13·1 answer
  • 9. Carlos walked 8 miles in 3 hours. Leah walked 14 miles in 6 hours. Are these rates
    5·1 answer
  • What is hell????????​
    15·2 answers
  • In a scholl there are 720 boys and 640 girls find the % of girls
    5·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!