Answer:
x=2, y=3
Step-by-step explanation:
This is a <u>system of equations</u>.
To solve a system of equations, we use the substitution method.
We can plug in the first equation,
, into the value for <em>x</em> in the second equation. Now, the second equation looks like this:

We simplify and solve for <em>y</em>:
→ 
→ 
→ 
Now, we plug in the value for <em>y</em>, which is 3, into either equation. I will just use the first equation:
→ 
→ 
Let me know if my explanation is unclear.
Answer:
7. A = 40.8 deg; B = 60.6 deg; C = 78.6 deg
8. A = 20.7 deg; B = 127.2 deg; C = 32.1 deg
Step-by-step explanation:
Law of Cosines

You know the lengths of the sides, so you know a, b, and c. You can use the law of cosines to find C, the measure of angle C.
Then you can use the law of cosines again for each of the other angles. An easier way to solve for angles A and B is, after solving for C with the law of cosines, solve for either A or B with the law of sines and solve for the last angle by the fact that the sum of the measures of the angles of a triangle is 180 deg.
7.
We use the law of cosines to find C.






Now we use the law of sines to find angle A.
Law of Sines

We know c and C. We can solve for a.


Cross multiply.





To find B, we use
m<A + m<B + m<C = 180
40.8 + m<B + 78.6 = 180
m<B = 60.6 deg
8.
I'll use the law of cosines 3 times here to solve for all the angles.
Law of Cosines



Find angle A:





Find angle B:





Find angle C:





Since you want to use the SAS theorem, you must find sides that are either side of angles BAC and DAE. You have already made use of sides AE and AC, so the other sides you need to choose are AB and AD. The appropriate relationship for similarity is ...
... AD = 2AB
since you want the sides of triangle ADE to be twice then length of those in triangle ABC.
Answer:
1:3
Step-by-step explanation:
1/3:1
We want the ratio with whole numbers
Multiply each side by 3
1/3*3 : 1*3
1:3
Answer:

Step-by-step explanation:
The systems of equations are
Let us assume the rate of the current be c
Now actual speed against the current is (15 - c)
And, the actual speed with the current is (15 + c)
Here we applied the time formula i.e. distance by speed
Also the upstream time - downstream time = 4
Now the equations are
