Question

Find the value of y when x equals 4. -3x + 9y = -57

Answer 1

Answer:

y = -5

Step-by-step explanation:

Isolate y:

-3x + 9y = -57

9y = -57 + 3x

y = (-57/9) + (3/9)x

Substitute for x:

y = (-57/9) + (3/9)(4)

y = (-57/9) + (12/9)

y = (-45/9)

y = -5

Answer 2

Answer:

$\mathsf {y = -5}$

Step-by-step explanation:

$\textsf {Given :}\\\textsf {-3x + 9y = -57}$

$\textsf {Divide throughout by 3 :}$

$\mathsf {\frac{1}{3} \times (-3x + 9y) = \frac{1}{3} \times -57}$

$\mathsf {-x + 3y = -19}$

$\textsf {Substitute x = 4 :}$

$\mathsf {-(4) + 3y = -19}$

$\mathsf {3y = -15}$

$\textsf {Divide by 3 on both sides :}$

$\mathsf {\frac{3y}{3} = \frac{-15}{3} }$

$\mathsf {y = -5}$