16x^2 -25 = 0
2006-11-25 11:35:12 · 4 answers · asked by Anonymous in Education & Reference ➔ Homework Help
It's the difference between two perfect squares. Take the square root of 16 and x squared. Then a minus sign and the square root of 25. Put parentheses around all of that. Write it again, and change the minus sign to a plus sign. You will set each group in parentheses equal to zero. There will be 2 equations. Solve for x. X will have 2 solutions.
2006-11-25 11:41:52 · answer #1 · answered by salsera 5 · 0⤊ 0⤋
Or this way.
16X^2-25=0
16X^2=25 divide both sides by 16
X^2=16/25 take sqrt of each side
X=+/- sqrt16/25 start to rationalize denominator
X=+/- sqrt16/sqrt25 , which is as far as you have to go in this case, as you know these square roots
X= 4/5, or the inverse
X=-5/4
2006-11-25 20:41:18 · answer #2 · answered by Anonymous · 0⤊ 0⤋
Ok, here's how you do it, you simplify the equation like this
16x^2 -25=0
(4x-5)*(4x+5)=0
the only way that would be true is if 4x-5=0 or 4x+5=0, so you solve both equations for x
4x-5 = 0
x = 5/4
4x+5=0
x = -5/4
and there you get your two answers ;o)
hope this helps.
2006-11-25 19:46:46 · answer #3 · answered by mensajeroscuro 4 · 1⤊ 0⤋
well...first you have to factor...
you know that they have to be factors of 16 (1,2,4,8,16) and 25 (1,5,25)...
since there is no middle term (ie-2x) you must realize the factors must cancel each other (one positive, one negative of the same number) to rid your equation of the middle term...
therefore that leaves you only with +4/-4 as factors of 16, and +5/-5 as factors of 25...
since it is -25, signs must be opposite...so you get (4x-5)(4x+5)
set each equal to zero and solve...
hope that helped :)
2006-11-25 19:46:39 · answer #4 · answered by xtcwmeg 3 · 0⤊ 0⤋