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Find the zeros of each function by using a graph and a table. F(x)=x^2+10x+21

User Lisa Anne
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1 Answer

13 votes
13 votes

The zeroes of the function are the values of x at f(x) = 0

So equate f(x) by 0 at first


x^2+10x+21=0

Now we should factorize the quadratic into two factors

Since the last term is positive so the two brackets have the same signs

Since the middle term is positive then the two bracket has +

(x + ?)(x + ?) = 0

We need to find two numbers their product is 21 and their sum is 10

They are 7 and 3

7 * 3 = 21 and 7 + 3 = 10

(x + 3) (x + 7) = 0

Now equate each bracket by 0 to find the values of x

(x + 3) = 0

Subtract 3 from both sides

x + 3 - 3 = 0 -

User Mushahid Khatri
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