SOLUTION: y=3(x+5)(x-2) Which of the following formulas is equivalent to the this one? a. y=3x^2+9x-30 b. y=x^2+3x-10 c. y=3x^2+3x-10 d. y=3x^2+3x-30

Algebra ->  Algebra  -> Distributive-associative-commutative-properties -> SOLUTION: y=3(x+5)(x-2) Which of the following formulas is equivalent to the this one? a. y=3x^2+9x-30 b. y=x^2+3x-10 c. y=3x^2+3x-10 d. y=3x^2+3x-30      Log On

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Question 73412: y=3(x+5)(x-2)
Which of the following formulas is equivalent to the this one?
a. y=3x^2+9x-30
b. y=x^2+3x-10
c. y=3x^2+3x-10
d. y=3x^2+3x-30
Answer by jim_thompson5910(21685) About Me  (Show Source):
You can put this solution on YOUR website!
if you FOIL the last 2 factors (x+5)(x-2) you get
%28x%2B5%29%2A%28x-2%29=x%5E2-2x%2B5x-10
x%5E2-2x%2B5x-10=x%5E2%2B3x-10
Now distribute a 3 to every term
3%2A%28x%5E2%2B3x-10%29
3x%5E2%2B9x-30
So the right choice is a)
You can always let x and y be any numbers to verify this, or you can graph these and they should be equal.