Math homework help, please!?

Question

My teacher hates us and gives homework over winter break.

Solve for X:

16x^2 - 9 = 0

a) {16/9 , -16/9}
b) {4/3 , -4/3}
c) {3/4 , -3/4}
d) {9/16 , -9/16}
e) {3/4 , 9/16}
f) None of the above.

And please, don't say None of the above unless it's really N/A. Thanks!

Answer 1

Answer: c) {3/4, -3/4}

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16x² - 9 = 0
16x² = 9
x² = 9/16
x = ±√(9/16)
x = ±(3/4)

Answer 2

16x^2 -- 9 = 0 Or x^2 = 9/16 Or x^2 = (±3/4)^2 Or x = ±3/4 (c)

Answer 3

Solve for X:
16x^2 - 9 = 0

16x^2 = 9
x^2 = 9/16
sqrt[x^2] = sqrt{9/16]
x = 3/4 and x = -3/4.
ANS: c

teddy boy

Answer 4

16x^2 - 9 = 0
Two ways to solve

1) by factoring
16x^2 - 9 = (4x +3)(4x - 3) = 0
4x + 3 = 0
4x = -3
x = -3/4 (first answer)
4x - 3 = 0
4x = 3
x = 3/4 (second answer)
This method is factoring difference of squares.

Second method
16x^2 - 9 = 0 (note, no middle term with x)
16x^2 = 9
x^2 = 9/16
x = sqrt(9/16)
x = +/- 3/4 = 3/4, - 3/4

Answer C.

Answer 5

Your teacher wants you to be successful, and should give you 30 problems every day year round.
16x^2-9=0
16x^2 =9
x^2=9/16
x= -3/4 or 3/4

Now if you are doing imaginary numbers (and I doubt you are) there are also two other answers:

3/4(cos 120 +i sin 120) and 3/4(cos(240+i sin 240)
=3/4(-1/2+i/2*sqrt3) 3/4(-1/2-i/2*sqrt3)=
=-3/8+(3i*sqrt(3))/8 =3/8-(3i*sqrt(3))/8

Answer 6

16x^2 -9 = 0
16x^2 = 9
x^2 = 9/16
x = +3/4 or -3/4

Answer 7

I'm not going to answer this question because it is REALLY SIMPLE. Think, but I'll give you a hint that will definitely lead you to the solution. Add nine to both sides, then take the square root on both sides, that should help. Taking the square root will get rid of the square. Remember, taking the square root will give you + and a -, so you will have two answers. Don't let that throw you off, that should actually be a very very good hint b/c they give you two answers in the solutions.

Answer 8

Are you sure that's his reason for assigning homework over a long vacation period? Personal hatred? Somehow I doubt it.

Add 9 to both sides, then divide both sides by 16. This gets the x^2 by itself. Then just take the square root of both sides.

Answer 9

16x^2 - 9 = 0

(4x)^2 - (3)^2 = 0

Recall that a^2 - b^2 = (a+b)(a-b)

here a = 4x : b = 3

so (4x)^2 - (3)^2 = 0 => (4x+3)(4x-3) = 0

either 4x + 3 = 0

or 4x - 3 = 0

4x = -3 or

4x = 3

x = -3/4 or

x = 3/4

Answer 10

c) {3/4 , -3/4}