Answer:
18
Step-by-step explanation:
<em>Convert</em><em> </em><em>the</em><em> </em><em>mixed</em><em> </em><em>number</em><em> </em><em>to</em><em> </em><em>an</em><em> </em><em>improper</em><em> </em><em>fraction</em><em> </em><em>9</em><em>/</em><em>2</em><em>÷</em><em>1</em><em>/</em><em>4</em>
<em>Reduce</em><em> </em><em>the</em><em> </em><em>numbers</em><em> </em><em>with</em><em> </em><em>the</em><em> </em><em>greatest</em><em> </em><em>common</em><em> </em><em>factor</em><em> </em><em>2</em><em> </em>
<em>and</em><em> </em><em>then</em><em> </em><em>multiply</em><em> </em><em>the</em><em> </em><em>numbers</em><em> </em><em>9</em><em>×</em><em>2</em><em>=</em><em>18</em><em> </em><em>✅</em>
First we find the common difference by subtracting the first term by the second term. 75 - 69 = 6. So the common difference is 6.
now we need to find the 28th term...we need to do this because we need to use this number in the sum formula.
an = a1 + (n-1)*d
n = term to find = 28
a1 = first term = 69
d = common difference = 6
now we sub
a28 = 69 + (28 - 1) * 6
a28 = 69 + 27 * 6
a28 = 69 + 162
a28 = 231...this is the 28th term
now we use the sum formula
sn = (n(a1 + a28) / 2
s28 = (28(69 + 231) / 2
s28 = (28(300) / 2
s28 = 8400/2
s28 = 4200 <===the sum of the first 28 terms
<span>Earths crust mineral composition are silicon oxide (SiO2),Magnesium monoxide (MgO),Ferrous oxide(FeO),Calcium monoxide (CaO),Sodium dioxide(Na2O) ,Potassium dioxide(K2O), while the Earths crust are sodium,magnesium,potassium,calcium,iron,aluminum,silicon,and oxygen .Because Earth is based on chemical composition and split up into a crust,mantle,outer core and inner core.</span>
Ye good..
Nice I’m impressed for nothing