What do we call our system of numeration
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Answer:
a= 22.5
b= 37.5
Step-by-step explanation:
<u>In</u><u> </u><u>△</u><u>BCD</u><u>:</u>
Applying Pythagoras' Theorem,
a² +30²= b²
a² +900= b² -----(1)
<u>In</u><u> </u><u>△</u><u>ABC</u><u>:</u>
Applying Pythagoras' Theorem,
b² +50²= (40 +a)² -----(2)
Substitute (1) into (2):
a² +900 +50²= 40² +2(40)(a) +a²<em> </em><em> </em><em> </em><em> </em><em> </em><em>(</em><em>expand</em><em> </em><em>bracket</em><em>)</em>
a² +900 +2500= 1600 +80a +a²
a² +3400= a² +80a +1600 <em>(</em><em>simplify</em><em>)</em>
a² +3400 -a² -80a -1600= 0 <em>(</em><em>bring</em><em> </em><em>everything</em><em> </em><em>to</em><em> </em><em>1</em><em> </em><em>side</em><em>)</em>
-80a +1800= 0
80a= 1800 <em>(</em><em>+</em><em>8</em><em>0</em><em> </em><em>on</em><em> </em><em>both</em><em> </em><em>sides</em><em>)</em>
a= 1800 ÷80
a= 22.5
Subst. a= 22.5 into (1):
22.5² +900= b²
b²= 506.25 +900
b²= 1406.25
b= √1406.25 <em>(</em><em>square</em><em> </em><em>root</em><em> </em><em>both</em><em> </em><em>sides</em><em>)</em>
b= 37.5 <em>(</em><em>reject</em><em> </em><em>negative</em><em> </em><em>value</em><em> </em><em>since</em><em> </em><em>b</em><em> </em><em>is</em><em> </em><em>a</em><em> </em><em>length</em><em>)</em>
☆(a +b)²= a² +2ab +b²
The mathematical mistake that Riley made is that:
"She used the wrong common denominator." (Option A)
A common denominator is a factor that is similar to all the fractions in the sequence of equations.
Hence the correct answer is:
(2(2x² - 6x + 9))/((x-3) (x-2) (x+3))
See the correct sequence of steps below:
Step One - the Expression is given as:
(x/(x-3)(x-2)) + (3/(x+3))
Step 2 - Find the common denominator and rewrite the expression so that the numerators are above the common denominators.
Hence we have: (x (x+3) + 3(x-3) (x-2))/(x-3)(x-2)(x+3)
Step 3 Apply the Law of Multiplicative Distribution:
Hence we have (x² +3x+3x²-9x-6x+16)/(x-3)(x-2)(x+3)
Step 4 - Collect Like Items
This gives us: (x²+3x²)+(3x-9x-6x)+18/(x-3)(x-2)(x+3)
Step 5 Sort for like coefficients
This gives us: ((1+3)x² +(3-9-6) * x + 18)/(x-3)(x-2)(x+3)
Step 6 - check for the sum or difference
This gives us: (4x²+(3-9-6) * x+ 18)/(x-3)(x-2)(x+3)
We simplify and factor the expression to get
(2(2x²-6x+6)/(x-3)(x-2)(x+3).
See the attached for full question.
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