Question

Find the value of y if the value of 3x 2 + 5x – 2y equals to 8, when x = - 1. ​

Answer 1

Answer:

The value of y = -5 when x = - 1 and $3x^2 + 5x - 2y = 8$.

Step-by-step explanation:

Given: $3x^2 + 5x - 2y = 8$

When x = -1 then find y.

Put x = -1 in $3x^2 + 5x - 2y = 8$

$3x^2 + 5x - 2y = 8\\3(-1)^2 + 5(-1) - 2y = 8\\3(1) - 5 - 2y = 8\\3 - 5 -2y = 8\\-2 - 2y = 8\\-2y = 8 + 2\\-2y = 10\\y = 10 \div( -2)\\\\y = - 5$

Answer 2

Answer:

-7

Step-by-step explanation:

As x is -1 we multiply 3 x -1 and 5 x -1

So,

3 x -1 +2 + 5 x -1 - 2y = 8

(By BODMASS rule we do the multiplication first)

-3 + 2 + -5 - 2y = 8

-1 + -5 - 2y = 8

-6 - 2y = 8

Now,

We use the transposition method to solve the equation

-6 - 2y = 8

-2y = 8 + 6

-2y = 14

y = $\frac{14}{-2}$

y = -7