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oksano4ka [1.4K]
4 years ago
13

Solving systems by elimination 4x-2y=7 3x+6y=9 what's the answer

Mathematics
1 answer:
irina1246 [14]4 years ago
8 0
4x - 2y = 7....multiply by 3
3x + 6y = 9
-------------
12x - 6y = 21 (result of multiplying by 3)
3x + 6y = 9
-------------add
15x = 30
x = 30/15
x = 2

4x - 2y = 7
4(2) - 2y = 7
8 - 2y = 7
-2y = 7 - 8
-2y = -1
y = 1/2

solution (2,1/2)
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How do I simplify by combining these numbers -3x - 5y + 2x + 10y
Wewaii [24]
They are basically like groups. Take -3x+2x , Just do -3 +2 = -1 and then just add the x. So -1x. Next you have -5y+10y . Just do -5 + 10 = 5 and remember to add the x on so your final answer should be -1x + 5y 
4 0
4 years ago
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Given: BD bisects ABC. Auxiliary EA is drawn such that AE || BD. Auxiliary BE is an extension of BC
AnnZ [28]
The required proof is given in the table below:

\begin{tabular}{|p{4cm}|p{6cm}|} 
 Statement & Reason \\ [1ex] 
1. $\overline{BD}$ bisects $\angle ABC$ & 1. Given \\
2. \angle DBC\cong\angle ABD & 2. De(finition of angle bisector \\ 
3. $\overline{AE}$||$\overline{BD}$ & 3. Given \\ 
4. \angle AEB\cong\angle DBC & 4. Corresponding angles \\
5. \angle AEB\cong\angle ABD & 5. Transitive property of equality \\ 
6. \angle ABD\cong\angle BAE & 6. Alternate angles
\end{tabular}
\begin{tabular}{|p{4cm}|p{6cm}|}
7. \angle AEB\cong\angle BAE & 7. Transitive property of equality \\
8. \overline{EB}\cong\overline{AB} & 8. From 7. $\Delta ABE$ is isosceles \\
9. EB = AB & 9. De(finition of congruence \\ 10. $\frac{AD}{DC}=\frac{EB}{BC}$ & 10. Triangle proportionality theorem \\
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7 0
3 years ago
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20 points!!!!
valentinak56 [21]
No, because the sample was not random
8 0
3 years ago
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A theater can hold 120 giants or 144 elves. If 90 giants are already inside, how many elves can also be admitted?
navik [9.2K]

Answer:

36

Step-by-step explanation:

make proportion giants to elves

120/144 = 90/x cross multiply

120x =144*90

120x =12960 divide by 120

x = 108

so if there are 90 giants in the theater there are  108 elves also

considering that total 144 elves can be  in the theater subtract 144 and 108 so 36 more elves can be admitted

3 0
4 years ago
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surveyor stands 100 m from the base of a tower on which an antenna stands. He measures the angles of elevation to the top and bo
balu736 [363]

Answer: 36.3m

Step-by-step explanation:

To solve this, we can draw two triangle rectangles, where the distance between the man and the base of the tower is one of the cathetus, the adjacent one, the height will be the opposite cathetus.

The triangle where the elevation angle is 58° is associated with the height of the tower without the aerial

The other triangle, where the elevation angle is 63° is associated with the height of the tower with the aerial.

Then we can calculate those two heights, then compute the difference, and the difference will be equal to the height of the aerial.

In both cases we want to calculate the opposite cathetus, then we should use the relation:

Tan(θ) = (Op. cath)/(Adj. cath)

The height without the aerial is h1, let's find it:

Tan(58°) = h1/100m

Tan(58°)*100m = h1 = 160m.

The height with the aerial is h2, let's find it:

Tan(63°) = h2/100m

Tan(63°)*100m = h2 = 196.3m

Then the height of the aerial will be:

h2 - h1 =  196.3m -  160m = 36.3m

6 0
3 years ago
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