The sales tax for a certain state can be found by multiplying the purchase price by 1/20 . What is the sales tax on an item that
2 answers:
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<h2>Steps:</h2>
So firstly, since we know that the coefficient of x² is 1, this means that this is our base equation:
y = x² + bx + c
Now, since we know that the roots are -7 and 1, set y = 0 and set x = -7 and 1 and simplify:
Now with this, we can set up a system of equations to solve for b and c. For this, I will be using the elimination method. For this, subtract the 2 equations:
Now that the c variable has been eliminated we can solve for b. For this, divide both sides by -8 and your first part of your answer is b = 6.
Now that we know the value of b, plug it into either equation to solve for c:
<u>Putting it together, your final answer is x² + 6x - 7 = 0.</u>