Question

PLEASE HELPPPPPPP!!!!!!!!!

Answer 1

Explanation:

y = 3x + 3

y = x - 1

"substitution" means we are defining one variable by an expression of the other variable and use this identity in one of the original equations.

in our case here the main work was already done (even twice) : y is defined as expressions in x.

we even have the luxury to pick which one and then to use it in the other.

it does not matter which one you pick, it will lead to the same result.

so, let's use the identity of equation 1 in equation 2 : we replace every occurrence of y by the defined identity

y = x - 1

turns into

3x + 3 = x - 1

now we subtract x from both sides

3x + 3 - x = x - 1 - x

2x + 3 = -1

now we subtract 3 from both sides

2x + 3 - 3 = -1 - 3

2x = -4

and finally we divide both sides by 2

2x/2 = -4/2

x = -2

this result we use now in one of the original equations to get y :

e.g.

y = x - 1

y = -2 - 1 = -3

so, the solution is (-2, -3)

Answer 2

This pair of equations is solvable by substitution, as I can easily substitute for y because it is already isolated in both equations. After substituting for y, I will solve the equations to get the value of x and then substitute that x-value into the simpler of the two equations, y = x - 1. Once I have both the x-value and y-value, they will be put into a point (x,y).

y = 3x + 3

y = x - 1

x - 1 = 3x + 3

x = 3x + 4

-2x = 4

x = -2

y = x - 1

y = ( -2 ) - 1

y = -3

The final answer to the pair of inequalities is ( -2,-3 )