1. ## Algebra Help Needed

Can anyone please show me the simpliest way to work out these ?

25-7a=27-4a

11-7(2-a) = 18

4
- (x+3) = 6
5

Thanks heaps

2. Originally Posted by chhoeuk

Can anyone please show me the simpliest way to work out these ?

25-7a=27-4a
we want to solve for $\displaystyle a$, so our objective is to get $\displaystyle a$ by itself on one side of the equal sign.

$\displaystyle 25 - 7a = 27 - 4a$ .......let's get all $\displaystyle a$'s on the left

$\displaystyle \Rightarrow 25 - 7a + 4a = 27$ ........i added 4a to both sides

$\displaystyle \Rightarrow -7a + 4a = 27 - 25$ .......i subtracted 25 from both sides

$\displaystyle \Rightarrow -3a = 2$ .........i computed both sides

$\displaystyle \Rightarrow a = - \frac {2}{3}$ ........i divided both sides by -3

11-7(2-a) = 18
$\displaystyle 11 - 7(2 - a) = 18$ ........first let's expand the brackets. multiply everything inside by -7

$\displaystyle \Rightarrow 11 - 14 + 7a = 18$ ........now clean things up a bit

$\displaystyle \Rightarrow -3 + 7a = 18$ ..........now add 3 to both sides

$\displaystyle \Rightarrow 7a = 21$ ................now divide both sides by 7

$\displaystyle \Rightarrow a = 3$

4
- (x+3) = 6
5

$\displaystyle \frac {4}{5} (x + 3) = 6$ ......again, expand the brackets first

$\displaystyle \Rightarrow \frac {4}{5}x + \frac {12}{5} = 6$

can you take it from here? remember, your objective is to get x on one side by itself, anything else on that side, we get rid of it by adding, subtracting or dividing both sided by it