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√(-12)  =  √(4 x 3 x -1)  =  √(4) x √(3) x √(-1)

√(4)  =  2

√(-1)  can be replaced with the symbol  i:

   =  2√(3)i  or  2i√(3) 

-18 - [75 / -15] =

-18 - [-5] =

-13

sin^2(x)+cos^2(x)+tan^2(x)+cot^2(x)+sec^2(x)+csc^2(x)=7

Note that  ...sin^2x + cos^2x = 1    ...so we have

tan^2x + cot^2x + sec^2x + csc^2x = 6

And

1 + tan^2x = sec^2x   ....so we have

2tan^2x + cot^2x + csc^2x = 5

And 1 + cot^2x = csc^x     so we have

2tan^2x + 2cot^x  = 4    divide through by 2   

tan^2x + cot^2x = 2

So

sin^2x/ cos^2x + cos^2x/sin^2x = 2

[sin^4x + cos^4]  = 2sin^2xcos^2x    rearrange

sin^4x - 2sin^2xcos^x + cos^4x = 0   factor

(sin^2x -cos^2x)(sin^2x - cos^2x)  =0   setting one of the factors to 0, we have

sin^2x - cos^2x = 0   factor again

(sinx + cosx)(sinx-cosx)  = 0

For the first factor, we have sinx = -cosx.... and this occurs at 3pi/4 and at 7pi/4

For the second factor, we have  sinx = cos x  and this occurs at pi/4 and 5pi/4

So....our solutions are   pi/4, 3pi/4, 5pi/4 and 7pi/4

sin²(x) + cos²(x)  =  1

sec²(x)  =  1 + tan²(x)

csc²(x)  =  1 + cot²(x)

[sin²(x) + cos²(x)] + tan²(x) + cot²(x) + [sec²(x)] + [csc²(x)]  =  7

--->   1 + tan²(x) + cot²(x) + [1 + tan²(x)] + [1 + cot²(x)]  =  7

--->   3 + 2tan²(x) + 2cot²(x)  =  7

--->   2tan²(x) + 2cot²(x)  =  4

--->   tan²(x) + cot²(x)  =  2

--->   tan²(x) + 1 / tan²(x)  =  2

--->   tan⁴(x) + 1  =  2tan²(x)

--->   tan⁴(x) - 2tan²(x) + 1  =  0

--->   (tan²(x) - 1)(tan²(x) - 1)  =  0

--->   tan²(x)  =  1

--->   tan(x)  =  1    or    tan(x)  =  -1

--->   x  =  π/4  or  5π/4     or     x  =  3π/4  or  7π/4

I am 72 years old.

Let m be my age in years. If s is my son's age in years, then my son is 52s weeks old. If g is my grandson's age in years, then my grandson is 365g days old. Thus,
365g = 52s.
Since my grandson is 12g months old,
12g = m.
Since my grandson, my son and I together are 120 years,
g + s + m = 120.
The above system of 3 equations in 3 unknowns (g, s and m) can be solved as follows.
m / 12 + 365 m / (52 x 12) + m = 120 or
52 m + 365 m + 624 m = 624 x 120 or
m = 624 x 120 / 1041 = 72.
So, I am 72 years old.

Well thats a simple one Milan. You have 72 cigarette butts.You know it takes 6 butts to make a ciggarette. Simply divide the 72 butts by the 6 butts it takes to make the the ciggarette. 72/6= 12
BUT WAIT.
After he has smoked those 12 cigarettes, he can still make another 2 cigarettes from the 12 remaining butts. Making the answer 14!
:)))

log₃(6x + 5)  =  2

Write into exponential notation:  3²  =  6x + 5

--->   9  =  6x + 5

--->   4  =  6x

--->   x  =  4/6  =  2/3

If the area of circle B = 64*pi cm^2, it's radius must be 8 cm.

Then, the radius of circle A must be 1/2 of that = 4cm

And it's area = pi*(4cm)^2  = 16pi cm^2

70.00x40% = 28
70/28= 2.5
70x8% = 5.95
2.5+5.95 = 8.45

Since  y  =  (1/4)x + 2  and  y  =  x - 1   --->   (1/4)x + 2  =  x - 1

Multiply all the terms by 4   --->   x + 8  =  4x - 4

Subtract x from both sides  --->         8  =  3x - 4

Add 4 to both sides            --->        12  =  3x

Divide both sides by 3        --->          x  =  4

To make u confused

yeah watto spot on mate

3+0.66 / 0.75 = 4.88

the square root of 72  is 8.49 correct to two decimals spaces

-3/5*2=-6/5=-1.2

Algebra has many diffrent sub topics that help you learn diffrent math problems

thank you geno3141 : ) your a smart person.

there is no possible solution that could work.

"Circumference" is the linear distance around an object such as a circle. Usually, one uses "perimeter" when one discuss polygons and "circumference" when refering to closed curves and circles. 

A right triangle will be formed if a² + b²  =  c².

The longest side must become the value of c; so is:  30² + 122²  =  125² ?

The angle at the rear end of the dump truck must be at least 45°.

For that angle, a right triangle has been formed where the front end is the opposite side and the length of the load is the hypotenuse.

When the front end of the dump truck has been raised 8', the opposite side is 8 while the hypotenuse is 14.

opposite divided by hypotenuse is sine:  sin = opp / hyp  =  8/14.

The angle = sin^-1(8/14) = 34.8°.

If you haven't had any trig, this can also be solved by similar triangles. Post back if you need that solution.