9x2 – 16 Factoring quadratic eqations
1 answer:
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So,
To find the percentage that the copper comprises, just divide the amount of copper by the total amount of metal in the coin. In this case, we will change the denominator so that it is 100, which can easily be converted into a percentage, which is really just a fraction out of 100.
75%
75% of the metal in the coin is copper.
To find the percentage that the copper comprises, just divide the amount of copper by the total amount of metal in the coin. In this case, we will change the denominator so that it is 100, which can easily be converted into a percentage, which is really just a fraction out of 100.
75%
75% of the metal in the coin is copper.
The equation is 
.
We are looking for a function with a vertex above the x-axis and a function that opens upward (has coefficient a > 0).
The first function opens downward and intersects the x-axis. The second function has a vertex below the x-axis. The third function satisfies our requirements. The fourth function has a vertex on the x-axis.
We can solve this algebraically with the knowledge that the real solutions of a quadratic are its x-intercepts. If there are no x-intercepts (because it lies entirely above or below the x-axis), then there are no real solutions. This is true when the discriminant
. You can see that from the quadratic formula. This holds true for both answers A and C, so to find the correct one, we remember that when the coefficient a of the 
term is positive, the graph opens upwards, so we choose C.
We are looking for a function with a vertex above the x-axis and a function that opens upward (has coefficient a > 0).
The first function opens downward and intersects the x-axis. The second function has a vertex below the x-axis. The third function satisfies our requirements. The fourth function has a vertex on the x-axis.
We can solve this algebraically with the knowledge that the real solutions of a quadratic are its x-intercepts. If there are no x-intercepts (because it lies entirely above or below the x-axis), then there are no real solutions. This is true when the discriminant