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
maw [93]
3 years ago
8

Solve the following system of equations -7x+2y=9, -8x+9y=17

Mathematics
2 answers:
emmasim [6.3K]3 years ago
5 0
\left\{\begin{array}{ccc}-7x+2y=9&|\cdot9\\-8x+9y=17&|\cdot(-2)\end{array}\right\\  \left\{\begin{array}{ccc}-63x+18y=81\\16x-18y=-34\end{array}\right\ |\text{add both sides of equations}\\-47x=47\ \ \ |:(-47)\\.\ \ \ \ x=-1\\\\\text{substitute the value of x to the first equation}\\\\-7(-1)+2y=9\\7+2y=9\ \ \ |-7\\2y=2\ \ \ |:2\\y=1\\\\\text{Answer:}\ x=-1\ and\ y=1\to(-1;\ 1)
umka21 [38]3 years ago
3 0
<span>-7x+2y=9  | * 9</span>
<span>-8x+9y=17  | *(-2)
</span>

<span>-63x + 18y = 81</span>
<span>16x -18y = -34
</span>
<span>_______________ +
</span>
<span>-47x = 47 ⇒ x = -1
</span>

<span>7+2y=9 ⇒ 2y = 9-7 ⇒ y = 1
</span>
You might be interested in
Evaluate(4):g(x) = 8x2 + 9x - 7
Rudiy27

Answer:

Answer:

157

let g(4) = x

3 0
3 years ago
Read 2 more answers
Describe the graph of the function at its roots. f(x) = (x − 2)3(x + 6)2(x + 12) At x = 2, the graph crossesdoes not intersectto
kow [346]

This type of problem can be decided by looking at whether the function is positive or negative in the vicinity of the zeros. There are three roots: -12, -6, and 2 at which the function is clearly 0. Look at the four intervals the x axis:

interval x<-12: function is negative (just test using a number <-12, say, -13)

interval (-12,-6): function is positive

interval (-6, 2): function is negative

interval x>2: positive

From the above you deduce that at the roots the function must be crossing the x-axis (as opposed to just touching it) because the function value changes its sign every time.

6 0
3 years ago
Read 2 more answers
A ladder is leaning against a building. The distance from the bottom of the ladder to the building is 16 ft less than the length
KATRIN_1 [288]

Let's say the length of the ladder is "d". Since the distance from the bottom of the ladder to the building is 16 feet less than the length, we can write this as d - 16.

The distance from the ground to the top of the ladder is 2 feet less than the length of the ladder, so we can denote this as

d - 2.

The shape made by the ground, ladder, and side of the building is a right triangle, and we just found its legs. We can use the Pythagorean Theorem to solve for "d" and find how far up the side of the building the ladder is:

(d - 16)^2 + (d - 2)^2 = d^2

(d^2 - 32d + 256) + (d^2 - 4d + 4) = d^2

2d^2 - 36d + 260 = d^2

d^2 - 36d + 260 = 0

(d - 26) * (d - 10) = 0

d = 26 or d = 10

The answer d = 10 does not fit in this case because it isn't possible to have 16 feet less of 10 feet; it would be negative!

So, d = 26. The top of the ladder to the ground is 2 less than d, so we do 26 - 2 = 24 feet.

The answer is 24 feet.

5 0
3 years ago
Read 2 more answers
Distributive property (10) points and brainlest
kati45 [8]

Answer:

answers!

for the problem: 36 + 8 = 44 (keep in mind)

Step-by-step explanation:

1st one: 4 × (9 + 2) = 54

9 + 2 = 11

4 x 11 = 44

2nd: 4 x 11 = 44

3 0
2 years ago
Read 2 more answers
Use the figure below to complete the following problem.<br><br> 2 + 3 =<br> 90<br> 120<br> 180
sineoko [7]
This equals 180.
1 and 3 are corresponding angles which means they are the same. 1+2=180 therefore 2+3= 180
5 0
3 years ago
Read 2 more answers
Other questions:
  • What is the value of g(3)?<br>a. 2<br>b. 3<br>c. 9<br>d. 14​
    14·2 answers
  • With her promotion, Nicki's salary increased from $19.50 an hour to $22.50 an hour. What is the percent of increase, rounded to
    13·2 answers
  • A mexican reaterant resives 60 take outs orders. The manager found 60% of the oders wwre tacos 25% werre burritow how many order
    13·1 answer
  • What is the slope of the line that passes through the pair of points? (-5.5, 6.1), (-2.5, 3.1)
    10·2 answers
  • At a basketball game, a vender sold a combined total of 223 sodas and hot dogs. The number of hot dogs sold was 57 less than the
    9·1 answer
  • Joesfina works between 10 and 30 hours per week at a pizzeria. She earns $8.50 an hour, but can earn tips when she delivers pizz
    12·1 answer
  • A bag contains five red candies 15 blue candies and 20 yellow candy what is the probability of drawing a red candy? A blue candy
    6·2 answers
  • Last year, Mr. Smith's biology class averaged 73 on their first test. This year, his new class averaged 87 on the same
    11·1 answer
  • Write an inequality for the sentence: A number b is greater than 7
    11·2 answers
  • Sierra is getting a loan to purchase a car, but she has a few options for loan
    7·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!