Simplify 3x (4x – 5) + 3 and find its value for x = 3

Simplified: 12(x^2)-15x+3if x = 3: 66

Step-by-step explanation:

When you simplify expressions, you have to take out the parentheses, so we just multiply 3x by everything inside the parentheses. So 3x(4x-5) we get 12(x^2) - 15x and then we just add the 3 so we get 12(x^2)-15x+3. Now all we have to do is substitute x as 3, we get 66 as your answer. Sorry if I'm wrong, this is what I got.

63

Step-by-step explanation: Substitute the value of the variable into the equation and simplify.

{x = -1/2 ,   y = -1

step-by-step explanation:

solve the following system:

{2 x + y = -2

{10 x - 3 y = -2

in the first equation, look to solve for y:

{2 x + y = -2

{10 x - 3 y = -2

subtract 2 x from both sides:

{y = -2 x - 2

{10 x - 3 y = -2

substitute y = -2 x - 2 into the second equation:

{y = -2 x - 2

{10 x - 3 (-2 x - 2) = -2

10 x - 3 (-2 x - 2) = (6 x + 6) + 10 x = 16 x + 6:

{y = -2 x - 2

{16 x + 6 = -2

in the second equation, look to solve for x:

{y = -2 x - 2

{16 x + 6 = -2

subtract 6 from both sides:

{y = -2 x - 2

{16 x = -8

divide both sides by 16:

{y = -2 x - 2

{x = -1/2

substitute x = -1/2 into the first equation:

{y = -1

{x = -1/2

collect results in alphabetical order:

answer:   {x = -1/2 ,   y = -1