Most quadratic functions(which is what you have there, to a degree of 2) are solved using factoring and the zero product law. If you can not factor then you have to use the quadratic formula or graph it. However this one can be factored.
It's pretty simple to just factor it by inspection but I use the chart method, if you know decomposition that works as well.
Factoring gives us,

Then you set each factor to 0 and solve for x,



And the second one,


The solutions to this equation are
x = -1/2, 3
C=3.14r^2 that's the formula a
Answer:
Infinitely many solutions.
Step-by-step explanation:
Let's solve your system by elimination.
x−3y=9;−x+3y=−9
x−3y=9
−x+3y=−9
Add these equations to eliminate x:
0=0
<u>Answer:</u>
Infinitely many solutions.
Answer: Stellas rate per minute is 30 words per minute
Step-by-step explanation: