3 (x + 1) = 5 (x - 2) + 7 x=?

Those are called binomials & you have to use the distributive property.

first: 3 (x+1) distributed & simplified 3x+3 & 5 (x-2) distributed & simplified is 5x-10, therefore 3 (x+1) = 3x+3 & 5 (x-2) = 5x-10. always simplify before solving any algebraic problem!

second: so now we can say ... 3x + 3 = 5x - 10 + 7.

third: now we combine like terms by adding the - 10 & 7 (on the right side) together to get - 3.

fourth: now we have to isolate the variables by doing the opposite function on each side! it should look like this right now: 3x + 3 = 5x - 3 ... subtract the 3x, on both sides, from the 5x to get 2x. looks like this now: 3 = 2x - 3

now add the - 3 (on the right) on the both sides

looks like this now: 6 = 2x

fifth: now divide to get 3. X = 3!

1.4 repeating?

3x+3=5x-10+7x

3x+3=12x-10

3=9x-10

13=9x

1.4 repeating=x