PLZ HELP ME WITH THIS IT IS SO CONFUSING ON 10 MINUTES LET PLZZZ ILL GVE BRAINLIEST

see explanation

Step-by-step explanation:

Given

f(x) = 3x² + 1

To obtain f(- 1) substitute x = - 1 into f(x) , that is

(8)

f(- 1) = 3(- 1)² + 1 = 3(1) + 1 = 3 + 1 = 4

(9)

Similarly

f(0) = 3(0)² + 1 = 3(0) + 1 = 0 + 1 = 1

(10)

Given

f(x) = 3x² + 1 and f(x) = 49, then equate right sides

3x² + 1 = 49 ( subtract 1 from both sides )

3x² = 48 ( divide both sides by 3 )

x² = 16 ( take the square root of both sides )

x = ± = ± 4

That is x = - 4 or x = 4

Okay...but it is not an inequality, it is just a system of equations

y = x - 12so sub in x - 12 for y in the other equation

x + y = 8
x + x - 12 = 8
2x - 12 = 8
2x = 8 + 12
2x = 20
x = 20/2
x = 10

y = x - 12
y = 10 - 12
y = -2

solution is (10,-2)