The difference between a number,x, and 4 is 9. find the number

Mathematics

1 answer:

Elena-2011 [213]4 years ago

6 0

let's set up an equation:

x-4=9

solve normally:

x=13

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John sells plain cakes for $8 and decorated cakes for $12. On a particular day, John started with a total of 100 cakes, and sold

qaws [65]

x+ y = 96 → y = 96 - x (1)

And the price per plain cake * the number he sold + price of the decorated cake * the number he sold = total sales

8x + 12y = 800 (2)

Subbing (1) into (2), we have that

8x + 12 (96 - x) = 800 simplify

8x + 1152 - 12x = 800

-4x + 1152 = 800 subtract 1152 from both sides

-4x = -352 divide both sides by -4

x = 88 = the number of plain cakes he sold

And 96 - x = 96 - 88 = 8 = the number of decorated cakes he sold

6 0

4 years ago

Read 2 more answers

Find the inverse of the function. f(x) = the cube root of quantity x divided by eight. - 4

Lapatulllka [165]

$\bf f(x)=y=\sqrt[3]{\cfrac{x}{8}}-4\impliedby \textit{first, let's switch the variables about}
\\\\\\
\underline{x}=\sqrt[3]{\cfrac{\underline{y}}{8}}-4\implies x+4=\sqrt[3]{\cfrac{\underline{y}}{8}}\implies (x+4)^3=\cfrac{y}{8}
\\\\\\
\boxed{8(x+4)^3=y}\impliedby f^{-1}(x)$