The simple rules in adding equation is
- simplify like terms first
- then get one variable on one side of the equation
- then solve the rest
The x-intercept is the point where the line intersects the x-axis which means that it is the value of x when y in the equation is set to be equal to zero. In the equation of the line given, setting the y value to zero will result to an x value of -1/2. Therefore, the x-intercept would be -1/2.
I think its 4 out of 5?
(could be wrong)
Answer = 16 birds
1. Write out your equations
X = birds
Y= cats
x + y = 19
2.50x + 7.50y = 62.50
2. Isolate one variable.
x + y = 19
x = 19 - y
3. Plug this in as the variable in the other equation. Then, solve.
2.5(19 - y) + 7.5y = 62.5
47.5 - 2.5y + 7.5y = 62.5
-2.5y + 7.5y = 15
5y = 15
y = 3 (cats)
4. Solve for the other variable.
We know there were 19 animals in total on Monday. Since there were 3 cats, there must be 16 birds.
5. Double check by plugging the numbers into the original equations.
16 + 3 = 19
19 = 19 (true)
2.5(16) + 7.5(3) = 62.5
40 + 22.5 = 62.5
62.5 = 62.5 (true)