Answer:
Shirts = $7
Shorts $17
Step-by-step explanation:
Let:
T - shirts
S - shorts
We can make two equations out of this problem:
4T + 3S = $79
7T + 8S = $185
Through substitution we can solve for one of the unknowns. We make one equation to solve for an unknown
We use the formula of S and insert it into the other equation:
Thus T-shirts are $7 each.
Now that we know T, we can use it to solve for the other unknown. You can use it on any of the formulas.
We know then that Shorts are $17 each.
Answer:
cos(a + b) =
Step-by-step explanation:
cos(a + b) = cos(a).cos(b) - sin(a).sin(b) [Identity]
cos(a) =
cos(b) =
Since, terminal side of angle 'a' lies in quadrant 3, sine of angle 'a' will be negative.
sin(a) = [Since, sin(a) =
]
=
=
Similarly, terminal side of angle 'b' lies in quadrant 2, sine of angle 'b' will be negative.
sin(b) =
=
=
By substituting these values in the identity,
cos(a + b) =
=
=
=
Therefore, cos(a + b) =
