Hey there!
To start, you know that y=x^2 and y=7x.
In knowing that the two expressions are set to the same value, y, you can set both equations equal to one another:
x^2=7x
Now, set the equation to 0 to solve for your solutions:
x^2=7x
x^2-7x=7x-7x
x^2-7x=0
Now, look for any common factors that can be factored out of the equation:
x^2-7x=0 (both have a common factor of x)
x(x-7)=
Notice that you have two factors: x and (x-7). This signifies that you have two values for x. To solve for the two values, set both factors to 0:
x=0
x-7=0
Since you have x=0, 0 would be one of the values of x.
Now, solve x-7=0 for the value of x:
x-7=0
x=7
Now that you have the value of x, 7 and 0, plug the values into any of the original equations to find the corresponding y values:
y=x^2
x=0
y=(0)^2
y=0
One solution set would be (0,0).
y=x^2
x=7
y=(7)^2
y=49
Another set would be (7,49).
Therefore, your final answer would be the second answer choice:
(0,0) and (7,49)
Hope this helps you out! :)