Answer:
B
Step-by-step explanation:
The <u>Elimination Method</u> is the method for solving a pair of linear equations which reduces one equation to one that has only a single variable.
- If the coefficients of one variable are opposites, you add the equations to eliminate a variable, and then solve.
- If the coefficients are not opposites, then we multiply one or both equations by a number to create opposite coefficients, and then add the equations to eliminate a variable and solve.
When multoplying the equation by a coefficient, we multiply both sides of the equation (multiplying both sides of the equation by some nonzero number does not change the solution).
So, option B is not allowed (it is not allowed to multiply only one part of equation)
Answer:
Step-by-step explanation:
L
H
S
=
cos
4
x
=
2
cos
2
(
2
x
)
−
1
=
2
(
cos
(
2
x
)
)
2
−
1
=
2
(
2
cos
2
x
−
1
)
2
−
1
=
2
(
4
cos
4
x
−
4
cos
2
x
+
1
)
−
1
=
8
cos
4
x
−
8
cos
2
x
+
2
−
1
=
8
cos
4
x
−
8
cos
2
x
+
1
=
R
H
S
Again
L
H
S
=
cos
4
x
=
2
cos
2
(
2
x
)
−
1
=
2
(
1
−
2
sin
2
x
)
)
2
−
1
=
2
(
1
−
4
sin
2
x
+
4
sin
4
x
)
−
1
=
2
−
8
sin
2
x
+
8
sin
4
x
−
1
=
8
sin
4
x
−
8
sin
2
x
+
1
=
R
H
S
sin
2
x
+
cos
2
x
=
1
cos
2
x
=
1
−
sin
2
x
substitute in the equation as follows
8
cos
4
x
−
8
cos
2
x
+
1
=
8
cos
2
x
(
cos
2
x
−
1
)
+
1
=
8
(
1
−
sin
2
x
)
(
1
−
sin
2
x
−
1
)
+
1
=
8
(
1
−
sin
2
x
)
(
−
sin
2
x
)
+
1
=
8
sin
4
x
−
8
sin
2
x
+
1
(2x-5y) + (x+y)
= (2x+x) + (-5y+y)
= 3x + (-4y)
= 3x-4y
So option A is the correct one.
Exponent is the expression in where you convert product factor expression into a shorter expression. So really you use it to make the question simpler and shorter(easier to understand).
The answer is 0.664 because you have to divide 4/5 and 5/6
