Solve the system by graphing x+y=2 and x-3y=18

I DONT KNOW THESE! HELP!

kkurt [141]

Answer:

20. x = 5, y = -2

21. x = 11, y = 12

22. x = 22, y = 11

23. x = 11, y = 10

Step-by-step explanation:

20. Opposite sides in the parallelogram are congruent, so

$2y+18=3x-1\\ \\6x-3=17-5y$

Solve this system of two equations:

$\left\{\begin{array}{l}2y-3x=-19\\ \\6x+5y=20\end{array}\right.$

Multiply the first equation by 2 and add two equations:

$2(2y-3x)+6x+5y=2\cdot (-19)+20\\ \\4y-6x+6x+5y=-38+20\\ \\9y=-18\\ \\y=-2$

Substitute it into the first equation:

$2\cdot (-2)-3x=-19\\ \\-3x=-19+4\\ \\-3x=-15\\ \\x=5$

21. Opposite angles in the parallelogram are congruent, so

$11x+5=10y+6$

Consecutive angles are supplementary, so

$6x-y+11x+5=180^{\circ}$

Solve this system of two equations:

$\left\{\begin{array}{l}11x-10y=1\\ \\17x-y=175\end{array}\right.$

From the second equation

$y=17x-175$

Substitute it into the first equation:

$11x-10(17x-175)=1\\ \\11x-170x+1750=1\\ \\-159x=-1749\\ \\x=11\\ \\y=17\cdot 11-175=187-175=12$

22. Opposite angles in the parallelogram are congruent, so

$2x-5=3y-12$

Consecutive angles are supplementary, so

$2x-5+7y+x=180^{\circ}$

Solve this system of two equations:

$\left\{\begin{array}{l}2x-3y=-7\\ \\3x+7y=185\end{array}\right.$

From the first equation

$x=-3.5+1.5y$

Substitute it into the second equation:

$3(-3.5+1.5y)+7y=185\\ \\-10.5+4.5y+7y=185\\ \\-105+45y+70y=1,850\\ \\115y=1,850+105\\ \\115y=1,955\\ \\y=17\\ \\x=-3.5+1.5\cdot 17=22$

23. Opposite sides in the parallelogram are congruent, so

$2x+9=4y-9\\ \\3x-5=2y+8$

Solve this system of two equations:

$\left\{\begin{array}{l}2x-4y=-18\\ \\3x-2y=13\end{array}\right.$

Multiply the second equation by 2 and subtract it from the first equation:

$2x-4y-2(3x-2y)=-18-2\cdot 13\\ \\2x-4y-6x+4y=-18-26\\ \\-4x=-44\\ \\x=11$

Substitute it into the first equation:

$2\cdot 11-4y=-18\\ \\-4y=-18-22\\ \\-4y=-40\\ \\y=10$

3 0

3 years ago

Oscar is responsible for choosing the company his local

MA_775_DIABLO [31]

First find the area of the triangle

8 0

2 years ago

Which statements can be concluded from the diagram and used to prove that the triangles are similar by the SAS similarity theore

velikii [3]

Answer:

RS/VU=ST/UT and ∠S≅∠U

Step-by-step explanation:

we know that

The Side-Angle-Side Similarity Theorem states that: If two sides in one triangle are proportional to two sides in another triangle and the included angle in both are congruent, then the two triangles are similar

In this problem the included angle is

∠S≅∠U

therefore

side RS must be proportional to side VU and side ST must be proportional to side UT

so

RS/VU=ST/UT

Verify

substitute the given values

12/6=16/8

2=2 -----> is true

therefore

The two sides are proportional

6 0

2 years ago

Read 2 more answers

What is the surface area? 2 mm 2 mm 2 mm square millimeters

Alona [7]

Answer:

24 mm^2

Step-by-step explanation:

length x width x 6 sides in a cube

(2)(2)(6)=24

4 0

2 years ago

For Camila's lemonade recipe, 3 lemons are required to make 5 cups of lemonade. Fill out a table of equivalent ratios.

Talja [164]

Answer:

$27 |1|$

$|2| 50$

this is your correct answer

7 0

2 years ago