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How do you solve this equation?
x^2-4x=0
A) 4, 5
B) 0, -4
C) 0, 4
D) 4, -4
I'm pretty sure x=4, but I need help finding y. I plugged it in my graphing calculator and when x=4, y=0 and I don't know where to go from here, so help would be most appreciated. lol
1 Answer
- 8 years agoFavorite Answer
firstly, this equation is a quadratic equation, meaning that there are two possible values for x, not just x=4.
x^2-4x=0 can be solved by factorising it.
x^2-4x=0 can be written as x(x-4)=0.
when x and (x-4) are multiplied with each other, they give 0. Meaning: one of them must be equal to zero.
x=0 or x-4=0
x-4=0 can be written as x=4.
thus, x=0 or x=4
Ans: (C)