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lorasvet [3.4K]
3 years ago
8

Please Help Me On These Math Questions!!!!! Solve Each System By Elimination

Mathematics
2 answers:
nikdorinn [45]3 years ago
8 0
The complete answers are attached here.

nekit [7.7K]3 years ago
5 0
11) -x + y = -1 ; 2x - y = 0
y = -1 + x ; 2x - (-1+x) = 0 ⇒ 2x + 1 - x = 0 ⇒x = -1 
y = -1 + (-1) ⇒ y = -2

12) -2x + y = -20 ; 2x + y = 48
y = -20 + 2x ; 2x + (-20 + 2x) = 48 ⇒ 2x -20 + 2x = 48 ⇒ 4x = 48 + 20
                      4x = 68 ⇒ x = 68/4 ⇒ x = 17
y = -20 + 2(17) ⇒ y = -20 + 34 ⇒ y = 14

13) 3x -y = -2 ; -2x + y = 3
y = 3 + 2x ; 3x - (3 + 2x) = -2 ⇒ 3x - 3 - 2x = -2 ⇒ x = -2 + 3 ⇒ x = 1
y = 3 + 2(1) ⇒ y = 3 + 2 ⇒ y = 5

14) x - y = 4 ; x - 2y = 10
x = 4 + y ; (4 + y) - 2y = 10 ⇒ 4 + y - 2y = 10 ⇒ 4 - y = 10 
                  ⇒ -y = 10 - 4 ⇒ -y = 6 ⇒  y = -6
x = 4 + (-6) ⇒ x = 4 - 6 ⇒ x = -2

15) x + 2y = 5 ; 3x + 2y = 17
x = 5 - 2y ; 3(5-2y) + 2y = 17 ⇒ 15 - 6y + 2y = 17 ⇒ -4y = 17 - 15
               ⇒ -4y = 2 ⇒ y = -2/4 ⇒ y = -1/2
x = 5 - 2(-1/2) ⇒ x = 5 + 2/2 ⇒ x = 5 + 1 ⇒ x = 6 
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2. Sam has two part-time jobs, delivering pizza and mowing lawns. He makes $9/hr delivering pizza and $7/hr mowing lawns. Last w
frutty [35]

Answer:

<h2>22 hours and 10 hours </h2>

Step-by-step explanation:

let the jobs be x and y, so that

x+y=32--------1

9x+7y=248----2

x=32-y

substitute x=32-y for x in equation 2 we have

9(32-y)+7y=248

open bracket we have

288-9y+7y=248

-2y=248-288

-2y=-40

2y=40

divide both sides by 2 we have

y=40/2

y= 10 hours

subtitute y=10 for y in equation 1 to find x

x+10=32--------1

x=32-10

x=22

x=22 hours

4 0
3 years ago
What is the volume of this solid? Recall the formula V = Bh.
Viktor [21]

Answer:

280

Step-by-step explanation:

V=Bh

V=1/2(7x10)8      *it is a triangluar pyrmid so the base is a triangle*

V=1/2x70x8

V=35x8

V=280

Answer:280

5 0
3 years ago
Read 2 more answers
What is 47.2 % of 300 ?
kupik [55]
For this type of question, you just need to multiply the percentage with the number
so, the calculation would be

47.2%  x 300

47.2/100 x 300

47.2 x 3

= 141.6  


6 0
4 years ago
Read 2 more answers
Which expression has the same value as the one below?
Alex787 [66]
Your answer is A have a good day
6 0
3 years ago
Read 2 more answers
I have no idea!! Please help!!!
Ber [7]
The area of a traingle is \frac{1}{2}bh
So we need to know the base and the height
To work out the sides of a right angle triangle we can use a²+b²=c
c is the hypotenuse and a and b are the other sides
Because this triangle is isoceles we know that a and b are the same

a²+b²=c²
a²+a²=c²
2a²=c²
2a²=(x√6)²
2a²=(x√6)(x√6)
2a²=x²+x√6+x√6+6
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a²=\frac{x^{2}+x \sqrt{6}+x \sqrt{6}+6 }{2}
a=\sqrt{\frac{x^{2}+x\sqrt{6}+x\sqrt{6}+6}{2}}

A=\frac{1}{2}bh
A=\frac{1}{2}a*a
A=\frac{1}{2}×\sqrt{\frac{x^{2}+x\sqrt{6}+x\sqrt{6}+6}{2}}×\sqrt{\frac{x^{2}+x\sqrt{6}+x\sqrt{6}+6}{2}}
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A=\frac{x^{2}+x \sqrt{6}+x \sqrt{6}+6 }{4}
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