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2 votes
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Consider the quadratic function y=5(x-1)^2-4find the x intercepts

User Xiddoc
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1 Answer

20 votes
20 votes

\begin{gathered} x-\text{intercepts: } \\ x=\text{ 1+ }\frac{2}{\sqrt[]{5}}\text{ or x = 1- }\frac{2}{\sqrt[]{5}} \\ x\text{ = 1.894 or x = 0.106} \end{gathered}Step-by-step explanation:

quadratic function: y = 5(x-1)² - 4

x intercept is gotten when y = 0

representing y with 0 in the quadratic function , we solve for x

0 = 5(x-1)² - 4

collect like terms by adding 4 to both sides:

0+ 4 = 5(x-1)² - 4 + 4

4 = 5(x-1)²

divide both sides by 5:


(4)/(5)=(5\mleft(x-1\mright)^2)/(5)

4/5 = (x-1)²

square root both sides:


\begin{gathered} \sqrt[]{(4)/(5)}=\sqrt[]{(x-1)^2} \\ \pm\sqrt[]{(4)/(5)}=\text{ x-1} \end{gathered}

simplify:


\begin{gathered} x\text{ - 1 = }\pm\sqrt[]{(4)/(5)} \\ x\text{ =1}\pm\text{ }\sqrt[]{(4)/(5)}\text{ = 1}\pm\text{ }\frac{\sqrt[]{4}}{\sqrt[]{5}} \\ x\text{ = 1}\pm\text{ }\frac{2}{\sqrt[]{5}} \\ x\text{ = 1+ }\frac{2}{\sqrt[]{5}}\text{ or x = 1- }\frac{2}{\sqrt[]{5}} \\ x\text{ = 1+ 0}.894\text{ or x = 1-0.894} \\ x\text{in tercept: } \\ x\text{ = 1.894 or x = 0.106} \end{gathered}

User Kim Hallberg
by
2.9k points
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