How many gallons of a plant food that is 6% nitrogen must be combined with another plant food that is 30% nitrogen to make 10 gal of a plant food that is 15% nitrogen?

x = 6 1/4

y = 3 3/4

Step-by-step explanation:

let 'x' = gallons of 6% nitrogen

let 'y' = gallons of 30% nitrogen

system of equations:

x + y = 10;  let y = 10-x

6x + 30y = 10(15)

substitute '10-x':

6x + 30(10-x) = 150

6x + 300 - 30x = 150

-24x = -150

x = 6 1/4

y = 3 3/4

d, x=8

step-by-step explanation:

simplifying

4x + -5 = 2x + 11

reorder the terms:

-5 + 4x = 2x + 11

reorder the terms:

-5 + 4x = 11 + 2x

solving

-5 + 4x = 11 + 2x

solving for variable 'x'.

move all terms containing x to the left, all other terms to the right.

add '-2x' to each side of the equation.

-5 + 4x + -2x = 11 + 2x + -2x

combine like terms: 4x + -2x = 2x

-5 + 2x = 11 + 2x + -2x

combine like terms: 2x + -2x = 0

-5 + 2x = 11 + 0

-5 + 2x = 11

add '5' to each side of the equation.

-5 + 5 + 2x = 11 + 5

combine like terms: -5 + 5 = 0

0 + 2x = 11 + 5

2x = 11 + 5

combine like terms: 11 + 5 = 16

2x = 16

divide each side by '2'.