Answer:
(x, y) ≈ (2.848, -19.241)
Step-by-step explanation:
I find it much easier to work with the problem statement when math expressions are written using numbers and symbols. We assume you have ...
-4x +15y = -300
20x +4y = -20
Dividing the second equation by 4 and subtracting the x-term gives ...
y = -5-5x
Substituting that into the first equation, we get ...
-4x +15(-5-5x) = -300
-79x -75 = -300
x = -225/-79 = 2 67/79 ≈ 2.8481
Substituting this into the equation for y gives ...
y = -5(x +1) = -5(3 67/79) = -19 19/79 ≈ -19.2405
The approximate solution is ...
(x, y) = (2.8481, -19.2405)
Answer:
wheres your graph?
Step-by-step explanation:
i could do this with a graph lol
Answer:
1/sqrt10
Step-by-step explanation:
1) Find out cosA using formula (cosA)^2+(sinA)^2=1
The module of cosA= sqrt (1- (-3/5)^2)= sqrt 16/25=4/5
So cosA=-4/5 or cosA=4/5.
Due to the condition 270degrees< A<360 degrees, 0<cosA<1 that's why cosA=4/5.
2) Find sinA/2 using a formula cosA= 1-2sinA/2*sinA/2 where cosA=4/5.
(sinA/2)^2= 0.1
sinA= sqrt 0.1= 1/ sqrt10 or sinA= - sqrt 0.1= -1/sqrt10
But 270°< A< 360°, then 270/2°<A/2<360/2°
135°<A/2<180°, so sinA/2 must be positive and the only correct answer is
sin A/2= 1/sqrt10