Part a), solve this system of equations:
x + y = 5
x - y = 2.25
2x = 7.25
x = 3.625
y = 1.375
part b), solve this system of equations:
x + y = 5
x = 3y
y = 1.25
x = 3.75
<u>Answer</u>
C. 4 + 6
D. 3.15151515.. + 4.6
E. √64 × √25
<u>Explanation</u>
A rational number is a number that can be expressed as a quotient or a fraction. That is it can be written as a/b.
π×6 = 6π ⇒ can not be written as a rational number.
√3 + √5 ⇒ the sum of two irrational numbers can not be rational.
4 + 6 = 10. Ten is a rational number. it can be written as 10/1
3.15151515.. + 4.6 = 104/33 + 23/5
= 1279/165
√64 × √25 = 8×5=40 This can be written as 40/1
Answer:
x = pi/2 + 2 pi n x = pi + 2 pi n where n is an integer
x = 5pi /3 + 2 pi n
Step-by-step explanation:
8 cos^2 x + 4 cos x-4 = 0
Divide by 4
2 cos^2 x + cos x-1 = 0
Let u = cos x
2 u^2 +u -1 =0
Factor
(2u -1) ( u+1) = 0
Using the zero product property
2u-1 =0 u+1 =0
u = 1/2 u = -1
Substitute cosx for u
cos x = 1/2 cos x = -1
Take the inverse cos on each side
cos ^-1(cos x) = cos ^-1(1/2) cos ^-1( cos x) =cos ^-1( -1)
x = pi/2 + 2 pi n x = pi + 2 pi n where n is an integer
x = 5pi /3 + 2 pi n