$5.75 made up of all dimes and quarters, joey has 38 coins, how many of each coin does he have?

answer:

x = -4       x=-1

step-by-step explanation:

10x + 6 = -2x^2 -2

add 2x^2 to each side

+2x^2 +10x + 6 =2x^2 -2x^2 -2

2x^2 +10x + 6 =   -2

add 2 to each side

2x^2 +10x + 6+2 =   -2+2

2x^2 +10x + 8 = 0

divide each side by 2

2/2x^2 +10/2x + 8/2 = 0/2

x^2 +5x+4 = 0

what 2 numbers multiply to 4 and add to 5

4*1 = 4

4+1 =5

(x+4) (x+1) = 0

using the zero product property

x+4 = 0     x+1 =0

x+4-4 = 0-4       x+1-1 =0-1

x = -4       x=-1

answer:

you would multiply the x component by -2

step-by-step explanation:

(-2) (-2x-5y)=-2(-1)

4x+10y=2

4x+2y=8

set both equal to 4x

4x=2-10y

4x=8-2y

2-10y=8-2y

-6=8y

y=-6/8

y=-3/4

4x + 2(-3/4) = 8

4x=38/4

x=38/16

x=19/8