When checking if (9,4) was a solution to 3y - 2x = 19, lev said that it was. why is he incorrect

Lev is incorrect because (9, 4) is not a solution to the equation.

Step-by-step explanation:

We are given the equation: 3y - 2x =  19

When we are to check if an ordered pair is a solution to an equation, we substitute the pair in the equation and compare the RHS and LHS.

If they come to be equal then we can say that the given pair is indeed a solution to the equation.

So, here, RHS = 19

LHS = 3(4) - 2(9) = 12 - 18

= -6

19

i.e., LHS ≠ RHS

So, we can say that (x, y) = (9, 4) is not a solution to the given equation.

x= -3 and

step-by-step explanation:

to find the roots of a cubic, use division or factoring to find the factors then set equal to 0. as this is a difference of cubes, it factors into

where a is the cube root of .

here   this is 27 and the cube root of 27 is 3. so we write using the form:

.

set each factor to 0 and solve for x.

x-3=0

x=3

the quadratic expression does not factor and must be solved using the quadratic formula.

where a = 1, b=3, and c=9

this cubic has two complex roots.

step-by-step explanation: