Answer:
-7
Step-by-step explanation:
21 ÷ (4+3) - 10
=> 21 ÷ (7) - 10
=> 3 - 10
=> -7
Answer:
x = 136/11
, y = 68/11
Step-by-step explanation:
Solve the following system:
{6 x - y = 68
2 y = x
Hint: | Choose an equation and a variable to solve for.
In the second equation, look to solve for x:
{6 x - y = 68
2 y = x
Hint: | Reverse the equality in 2 y = x in order to isolate x to the left hand side.
2 y = x is equivalent to x = 2 y:
{6 x - y = 68
x = 2 y
Hint: | Perform a substitution.
Substitute x = 2 y into the first equation:
{11 y = 68
x = 2 y
Hint: | Choose an equation and a variable to solve for.
In the first equation, look to solve for y:
{11 y = 68
x = 2 y
Hint: | Solve for y.
Divide both sides by 11:
{y = 68/11
x = 2 y
Hint: | Perform a back substitution.
Substitute y = 68/11 into the second equation:
{y = 68/11
x = 136/11
Hint: | Sort results.
Collect results in alphabetical order:
Answer: {x = 136/11
, y = 68/11
Step-by-step explanation:

I would write the missing variable as x. It's what everyone uses.
Anyway, 91 divided by x is 65.
The way we can do this is reverse 65 and x.
91 divided by 65 = x.
91 divided by 1.4 = 65
65 x 1.4 = 91
x (or ?) = 1.4