I am orearte sure the correct answer is 280 please give me brainliest if u can
quadratic formula:
x = <u>-b ± √(b² - 4ac)</u>
2a
7x² - x = 7
subtract 7 from both sides:
7x² - x - 7 = 0
plug values into the quadratic formula:
x = <u>-(-1) ± √((-1)²- 4(7)(-7))</u>
2(7)
simplify:
x = <u>1 ± √(197)</u>
14
Answer:
651.
Step-by-step explanation:
Note: In the given series it should be -29 instead of 29 because 29 cannot be a term of AP whose first term is 91 and common difference is -6.
Consider the given series is
It is the sum of an AP. Here,
First term = 91
Common difference = 85 - 91 = -6
Last term = -29
nth term of an AP is
where, a is first term and d is common difference.
Sum of AP is
Therefore, the sum of given series is 651.