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2 years ago

If an arithmetic sequence has a4 = 107 and a8 = 191, what is a₁?PLEASE HELP ME

Mathematics

1 answer:

katen-ka-za [31]2 years ago

3 0

$\text{nth term of an arithmetic sequence,}\\\\a_n = a_1 + (n-1)d\\\\a_4 = a_1 +3d=107~~~......(i)\\ \\a_8=a_1+7d = 191~~~......(ii)\\\\\\\text{(ii) -(i):}\\\\~~~~~~a_1+7d-a_1-3d = 191 -107\\\\\implies 4d = 84\\\\\implies d = \dfrac{84}4\\\\\implies d= 21\\\\\text{Substitute d= 21 in eq~(i):}\\ \\~~~~~ a_1 +3(21) = 107\\\\\implies a_1 + 63 = 107\\\\\implies a_1 = 107-63\\\\\implies a_1 =44$

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3 years ago

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2 years ago

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For the interval [0,18]:

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Average = $\frac{f(18) - f(0)}{x_{2} - x_{1} }$

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Bird B: y = 3.6(1.06)x

For the interval [0,18]:

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2 years ago

If an arithmetic sequence has a4 = 107 and a8 = 191, what is a₁?PLEASE HELP ME​

If an arithmetic sequence has a4 = 107 and a8 = 191, what is a₁?PLEASE HELP ME