What is the answer to this equation 9x-7 = - 7

Step-by-step explanation:

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hello from mrbilldoesmath!

answer:   none of them

discussion:

to be a quadratic (second degree) equation the highest power of x in the equation must be   equal to 2 (and the constant multiplying that power of x must also be non zero).   let's look at your examples:

the highest exponent of x is "1". not quadratic

f(x) = 2x + x + 3        

-- the highest exponent of x is 2 but it is multiplied by 0, effectively cancelling out that power. the highest exponent of x is actually 1, so this a linear equation.   not a quadratic.

f(x) = 0x^2 - 4x + 7    

-- -- the highest exponent in this case   if 3 ( 3x^3+ so this equation is not a quadratic. it is a cubic equation.

regards, mrb