Barbara is planning a party . she invited some school friends and 2 times as many friends from her swimming club as school friends . if a total of 21 friends came to her party , how many school friends did she invite

7 School Friends

Step-by-step explanation:

Make a Variable

SWM = swimming club

SCH = school

if 21 people are at her party, then that means the ratio of SCH:SWM is 1:2

21/3 = 7

that means 7 school friends were invited

have a great day!

37/3

step-by-step explanation:

step 1: simplify both sides of the equation.

7x+8(x+

1

4

)=3(6x−9)−8

7x+(8)(x)+(8)(

1

4

)=(3)(6x)+(3)(−9)+−8(distribute)

7x+8x+2=18x+−27+−8

(7x+8x)+(2)=(18x)+(−27+−8)(combine like terms)

15x+2=18x+−35

15x+2=18x−35

tep 2: subtract 18x from both sides.

15x+2−18x=18x−35−18x

−3x+2=−35

step 3: subtract 2 from both sides.

−3x+2−2=−35−2

−3x=−37

step 4: divide both sides by -3.

−3x

−3

=

−37

−3

x=

37

3