There are 28 boys in class 5 (1), and there are 3 girls less than boys. What is the proportion of girls to boys? What is the number of boys in the class?

There are 28 boys in class 5 (1), and there are 3 girls less than boys. What is the proportion of girls to boys? What is the number of boys in the class?

(28-3) △ 28, = 25 △ 28, = 2528; 28 △ [(28-3) + 28] = 28 △ 25 + 28, = 28 △ 53, = 2853. A: the number of female students is 2528 of that of male students, and that of male students is 2853 of that of the whole class
Why is Tan (- x) = TaNx and not equal to - TaNx?
TaNx = the opposite side of the angle is greater than the adjacent side of the angle, X is in the first quadrant, both sides are greater than 0
Tan (- x) = the opposite side of the angle is greater than the adjacent side of the angle, - x in the fourth quadrant, the adjacent side is greater than 0, and the opposite side is less than 0,
So tan (- x) = - TaNx. Not tan (- x) = TaNx
In class 51, boys account for three fifths of the class, and girls account for some of the class? Girls account for some of the boys? Fast
First question: 1-3 / 5 = 2 / 5
Second question: 2 / 5 △ 3 / 5 = 2 / 3
First question:
Girls account for two fifths of the class, with 1 - three fifths.
Second question:
Two fifths ／ three fifths equals two thirds.
Why is Tan (π / 4 - x) equal to (1-tanx) / (1 + TaNx)?
Tangent angle formula based on sum of two angles
tan（π/4）- tan（x）
tan（π/4 - x）= ———————————
1 + tan（π/4）X tan（x）
Because π / Tan = 1
1- tan（x） 1- tan（x）
So the above formula = --=——————
1 + 1 X tan（x） 1+ tan（x）
The tangent expansion of π / Tan is π / Tan = 4 (tan) = 4
So it will = (1-tanx) / (1 + TaNx)
If the number of girls in a class is two-thirds of the number of boys, then the number of boys is a fraction of the total number of the class
The number of boys is 3 / (2 + 3) = 3 / 5 of the total number of the class, that is, 3 / 5
What is sinxcosx-1 equal to when TaNx = 2
tanx=sinx/cosx=2
So SiNx = 2cosx
(sinx)^2+(cosx)^2=1
So (cosx) ^ 2 = 1 / 5
sinxcosx-1=2(cosx)^2-1=2/5-1=-3/5
From TaNx = 2, that is, the value of SiNx / cosx is 2, so SiNx = 2cosx, simultaneous sin ^ x + cos ^ x = 1, we know cos ^ x = 1 / 5,
And sinxcosx-1 = 2cos ^ X-1, so the solution is negative 3 / 5
There are 31 boys and 29 girls in class 3 of grade 5. What is the proportion of boys and girls in the total number of the class?
31/(31+29)=31/60
29/60
A & # 178; + 4 * a = 25697, what is a equal to?
a²+4*a=25697
a²+4a+4=25697+4
(a+2)²=25701
a+2=±√(25701)
a=-2±√(25701)
A there are two
a1≈-2+160.3153=158.3153
a2≈-2-160.3153=162.3153
The number of boys in a class is 7 / 4 of the total number of the whole class, so the number of girls is a fraction of the number of boys
(7-4)/4=3/4
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I didn't notice. Look, 7 / 4, is that possible? 4 / 7 is possible
It is required to simply calculate what 1008 & # 178; - 1004 & # 178; of 2012 & # 178; is equal to
(1008 & # 178; - 1004 & # 178;) of 2012 & # 178;
=[(1008 + 1004) × (1008-1004)] in 2012 and 178;
=(2012 × 4) in 2012 and 178;
=Quarter of 2012
=403
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I'm sorry I didn't choose you. Although he was wrong, he was the first one to answer, and the format was very good