Question

How do you simplify `y = (x - 1)(5x + 2)`?

Answer 1

`y=5x^2-3x-2`

Explanation:

Multiply everything in one bracket by everything inside the other. WHATCH THE SIGNS!
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`color(blue)("Method example using numbers")`

Consider `6xx3=18`
But 6 can be 'split' (partitioned) into 4 + 2 so we have

`(4+2)xx3=18` The values have not changed, just the way they look.

Write as `3(4+2)`

So this is 3 lots of `(4+2)`

`->" "(4+2)+(4+2)+(4+2)`

`=4+4+4" "+2+2+2`

`=3xx4" "+" "3xx2" " =" " 12+6" "=" "18`

So we have multiplied everything inside the bracket by 3

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Given:`" "color(blue)((x-1)color(brown)((5x+2))`

`color(brown)(color(blue)(x)(5x+2)color(blue)(-1)(5x+2) )`

`5x^2+2x" "-5x-2`

`5x^2-3x-2`

`color(magenta)("Take it one step at a time ")`

and watch those signs