Let x be the number of pounds of the $1.35 beans. The cost of those beans is $1.35 * x, or 1.35x.
<span>Let y be the number of pounds of the $1.05 beans. The cost of those beans is $1.05 * y, or 1.05y. </span>
<span>We know that 120 pounds of the mix sells for $1.15/pound, for a total of 120 * 1.15 = $138. </span>
<span>x + y = 120 </span>
<span>1.35(x) + (1.05)y = 138 </span>
<span>We can rewrite the first as </span>
<span>x = -y + 120 </span>
<span>Now we can substitute (-y + 120) in for (x) in the second equation, because we just proved they're equal. </span>
<span>1.35(x) + 1.05(y) = 138 </span>
<span>1.35(-y + 120) + 1.05y = 138 </span>
<span>-1.35y + 162 + 1.05y = 138 </span>
<span>-0.3y + 162 = 138 </span>
<span>-0.3y = -24 </span>
<span>y = 80 </span>
<span>And since x + y = 120, that means x = 40. </span>
<span>Check: </span>
<span>40 pounds of x at $1.35 costs 40 * 1.35, or $54. </span>
<span>80 pounds of y at $1.05 costs 80 * 1.05, or $84. </span>
<span>Do those add up to our target total, according to the question, of 120 * 1.15 = $138? </span>
I will assume that you meant:
(x+4)/(-3x^2+12x+36) factor the denominator...
(x+4)/(-3(x^2-4x-12))
To factor a quadratic of the form ax^2+bx+c you need to find two values, j and k, which satisfy two conditions...
jk=ac=-12 and j+k=b=-4 so j and k must be 2 and -6 and the factors are then:
(x+2)(x-6) so we are now left with:
(x+4)/(-3(x+2)(x-6))
The only restriction on this function is that division by zero is undefined, so x cannot equal -2 or 6
Answer:
21 yrs old
Step-by-step explanation:
m= michael age
b=Brandon age
m=b+12
m-17=4(b-17)= 4b-68 --»»m = 4b -51
//put b+12 instead m// b+12=4b-51
3b=63 --»»b=21
Brandon age is 21
Michael age is 33
