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2 years ago

What times what equals 30 but add to get 40?

2 answers:

5 0

Lets call those two unknown numbers a, b and write the info in the problem as equations:
a*b = 30
a + b = 40
lets solve for a in the second equation and substitute in the first:
a + b = 40
a = 40 - b
therefore:
a*b = 30
(40 - b)b = 30
40b - b^2 = 30
b^2 - 40b + 30 = 0
if we apply the general quadratic equation to solve we have:
b = (40 +- √(1600 - 120))/2
b = (40 +- √(1480))/2
b = (40 +- 38.47)/2
There are two solutions:
b1 = (40 + 38.47)/2
b1 = 39.24
b2 = (40 - 38.47)/2
b2 = 0.765
lets use the second solution b2 = 0.765, and substitute in the first equation to find a:
a*b = 30
a*0.765 = 30
a = 30/0.765
a = 39.216
so the numbers are 39.216 and 0.765

ale4655 [162]2 years ago

4 0

(15x2) = 30, (30 + 10) = 40 .. (P.E.M.D.A.S)

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Sati [7]

Answer:

y intercept = -5 

slope= 4 

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EXPLANATION:

FIRST, you must write the formula for a linear graph , which is y = m(x) + c

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finding the y intercept.

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in the above equation, I substituted the value I had for the slope or the gradient or m.

SO NOW IM ABOUT TO FIND C

TO FIND C, YOU MUST FIRST PICK A CORRESPONDING Y AND X COMPONENT.

I CHOOSE MY Y = 3 and X = 2

Now I'm going to substitute those values into the formula.

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since it's an equation with one variable, no need for simultaneous equations.

3 = 8 + c

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3 years ago

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3 years ago

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$\huge \boxed{y$

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3 years ago

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jenyasd209 [6]

The function is $f(x)=x^3-11x^2+36x-36$ .

To find the x-intercepts, we need to factorize the function. A very good idea is to first try the factors of 36:

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f(2)=8-44+72-36=-36+72-36=0. Here we have our first root (2).

Now we cad divide f(x) by (x-2) which will give us a quadratic expression, which we can factorize easily (if the discriminant is non negative).

We can also try some other factors of 36. Indeed we can check that

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This is the reason why in the first place we looked at the factors of 36 for the possible zeros of f(x).

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Note that f(0)<f(2) because f(0)=-36 and f(2)=0. This means that at the left side, the graph is coming from - infinity. Similarly,

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Thus, the end behaviors are: the graph goes to + infinity as x goes to + infinity,

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