Plzzz answer

9. -16

10. 3

11. 4

Step-by-step explanation:

9. 21 = 5 - r

Subtract 5 from both sides;

16 = -r

Divide both sides by -1

-16 = r OR r = -16

10. 8 - 5b = -7

Subtract 8 from both sides;

-5b = -15

Divide both sides by -5

b = 3

11. -10 = 6 - 4m

Subtract 6 from both sides;

-16 = -4m

Divide both sides by -4

4 = m OR m = 4

option c) graph of line going through 1, 4 and 3, 10

step-by-step explanation:

let y equal to margo's coin collection

let x equal to number of years

at the begining x=0, y=1 → point=(x,y)→point=(0,1)

she adds 3 coins per year, then y=1+3x

at x=1, y=1+3(1)=1+3→y=4→point=(x,y)→point=(1,4)

at x=3, y=1+3(3)=1+9→y=10→point=(x,y)→point=(3,10)

the graph of line going through (1, 4) and (3, 10), then the option c is the correct.

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step-by-step explanation: