Remember the distributive property? It goes like x(a+b)=xa+xb... For example 3(6+7)=(3*6)+(3*7)=39
Same here
5(3x-6)-8(3x-7)
do the thing
(15x-30)-(24x-56)
Take parentheses off.
15x-30-24x+56
//WHY PLUS 56 NOT MINUS?
//because there was a minus sign outside the original parentheses, so the signs inside have to be flipped when the parentheses is taken off
//Let's simplify now
15x-24x-30+56
-9x+26
^^The answer!

5 0

3 years ago

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Find the sides, and the value of x and y.

Gelneren [198K]

Answer:

$\huge\boxed{x=15;\ y=4}$

Step-by-step explanation:

Proportion:

$\dfrac{x}{18}=\dfrac{5}{6}\qquad|\text{cross multiply}\\\\(x)(6)=(18)(5)\\\\6x=90\qquad|\text{divide both sides by 6}\\\\\huge\boxed{x=15}$

$\dfrac{y}{5}=\dfrac{12}{x}$

substitute x = 15:

$\dfrac{y}{5}=\dfrac{12:3}{15:3}\\\\\dfrac{y}{5}=\dfrac{4}{5}\qquad|\text{cross multiply}\\\\(y)(5)=(5)(4)\\\\5y=20\qquad|\text{divide both sides by 5}\\\\\huge\boxed{y=4}$