Turn it around for my convenience.
81X^2 - 25 = 0
add 25 to each side
81X^2 = 25
divide both sides by 81
X^2 = 25/81
take square root both sides
X = sqrt(25/81
express as
X = sqrt(25)/sqrt(81)
do it
X = 5/9
----------------check in original equation
81(5/9)^2 - 25 = 0
81(25/81) - 25 = 0
25 - 25 = 0
0 = 0
checks
4x - 10 + 5x = 719x = 81x = 9
82
x4 - 81 = 0x4 = 81x = 3
15 percent 0 equals 0; 0 percent 15 equals 0. Both the above are true
yes
4x - 10 + 5x = 719x = 81x = 9
82
x4 - 81 = 0x4 = 81x = 3
85
If you mean (9x-8y)(9x+8y) then it is 81x^2 minus 64y^2
15 percent 0 equals 0; 0 percent 15 equals 0. Both the above are true
yes
0
0
maybe
It equals 0.
It equals 0