SOLUTION: (3x+7)(x-5)=

Algebra ->  Polynomials-and-rational-expressions -> SOLUTION: (3x+7)(x-5)=      Log On


   

Question 467360: (3x+7)(x-5)=
Answer by jim_thompson5910(35256) About Me  (Show Source):
You can put this solution on YOUR website!

%283x%2B7%29%28x-5%29 Start with the given expression.


Now let's FOIL the expression.


Remember, when you FOIL an expression, you follow this procedure:


%28highlight%283x%29%2B7%29%28highlight%28x%29-5%29 Multiply the First terms:%283%2Ax%29%2A%28x%29=3%2Ax%5E2.


%28highlight%283x%29%2B7%29%28x%2Bhighlight%28-5%29%29 Multiply the Outer terms:%283%2Ax%29%2A%28-5%29=-15%2Ax.


%283x%2Bhighlight%287%29%29%28highlight%28x%29-5%29 Multiply the Inner terms:%287%29%2A%28x%29=7%2Ax.


%283x%2Bhighlight%287%29%29%28x%2Bhighlight%28-5%29%29 Multiply the Last terms:%287%29%2A%28-5%29=-35.


---------------------------------------------------
So we have the terms: 3%2Ax%5E2, -15%2Ax, 7%2Ax, -35


3%2Ax%5E2-15%2Ax%2B7%2Ax-35 Now add every term listed above to make a single expression.


3%2Ax%5E2-8%2Ax-35 Now combine like terms.


So %283x%2B7%29%28x-5%29 FOILs to 3%2Ax%5E2-8%2Ax-35.


In other words, %283x%2B7%29%28x-5%29=3%2Ax%5E2-8%2Ax-35.