Question

0.7 (3s + 4)-1.1s = 7.9

Answer 1

First multiply 0.7 by (3s+4) to get 2.1s + 2.8 and then add the 1.1s to the 2.1s and that should leave you with 1s+2.8 now you should have 1s + 2.8 = 7.9, you want to take 2.8 from both sides to bring it over to the 7.9 to make it look like 1s = 7.9 - 2.8 so now go ahead and have the 7.9 and the 2.8 subtract so you should end up with 1s = 5.1 so now you want to divide both sides by 1 and the 1s would cancel out into s and the 5.1 stays the same so now you have s = 5.1, you can always check this answer by seeing that it works so here is how you do that. Plug in your number, so you have
0.7 (3 * 5.1+4) - 1.1 * 5.1 = 7.9
here is your verification, 0.7 multiplied by all the numbers in the parentheses (3 * 5.1+4) would get you with 10.71 + 28 and you have - 1.1 * 5.1 = 7.9 so now just add the 10.71 to the 2.8 to get 13.51 and multiply the 1.1 by the 5.1 to get 5.61 and subtract the two to get 7.9 and that’s 7.9 = 7.9 so I hope this was helpful!! ^_^

Answer 2

s = 5.1

Explanation:

`0.7 (3s + 4)-1.1s = 7.9\\`

Multiply both sides of the equation by 10

`0.7\left(3s+4\right)\cdot \:10-1.1s\cdot \:10=7.9\cdot \:10\\\\= 7\left(3s+4\right)-11s=79\\`

Expand

`\mathrm{Expand\:}7\left(3s+4\right)-11s:\\\quad 10s+28`

Subtract 28 from both sides

`10s+28-28=79-28`

Simplify

`10s=51`

Divide both sides of the equation by 10

`(10s)/(10)=(51)/(10)`

Simplify

`s=(51)/(10)\\\\Decimal = 5.1`