Answer:
Keisha bought 3 sandwiches and 5 lemonades.
Equations: x + y = 8 2x + y = 11
Step-by-step explanation:
To solve a problem with two variables, you need to set up a system of equations comparing the two variables and solve using either substitution or elimination. If 'x' represents the number of sandwiches and 'y' represents the number of lemonades, then x + y = 8 because they bought a total of 8 items. Also, the cost of each item is given as well as the total amount of money spent. So, our second equation is: 2x + y = 11. We can use inverse operations to solve for 'y' in the first equation: x + y - x = 8 - x which simplifies to: y = 8 - x. We can then use this expression to substitute in for the variable 'y' in the second equation: 2x + 8 - x = 11.
Combine like terms: x + 8 = 11
Inverse Operations: x +8 - 8 = 11 - 8
Solve: x = 3, so Keisha bought 3 sandwiches
Solve for y: y = 8 - 3 = 5, so Keisha bought 5 lemonades
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) = 
Answer:
385
Step-by-step explanation:
260 divided by 4 =65
65 + 65 + 260= 385
2.75 * 12 = 33.
If the Sanchez family is using 2 3/4 (or 2.75) tubes of toothpaste and there are 12 months in a year, we use the equation above and get 33 as our answer.