Question 325374
f(x)=x^2+3x-10 
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Ways to find zeroes:
1. graphing
2. factoring
3. Quadratic equation
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Your Problem factors nicely:
Think of 2 numbers whose product is -10 
and whose sum is 3.
The numbers are +5 and -2
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Replace the 3x term by -5x+2x to get:
x^2 +5x-2x - 10 = 0
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Factor the 1st two and the last two terms separately:
x(x+5) -2(x+5) = 0
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Factor again:
(x+5)(x-2) = 0
Solve:
x+5 = 0 or x-2 = 0
x = -5 or x = +2
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Those are the zeroes.
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Cheers,
Stan H.