Answer:
Ralph's current age is 18.
Step-by-step explanation:
Let r and s represent the current ages of Ralph and Sara respectively. Our task here is to determine r, Ralph's age now.
If Ralph is 3 times as old as Sara now, then r = 3s.
Six years from now, Ralph's age will be r + 6 and Sara's will be s + 6. Ralph will be only twice as old as Sara will be then. This can be represented algebraically as
r + 6 = 2(s + 6).
We now have the following system of linear equations to solve:
r + 6 = 2s + 12, or r - 2s = 6, and r = 3s (found earlier, see above).
r - 2s = 6
r = 3s
Substituting 3s for r in r - 2s = 6, we get 3s = 2s + 6, or s = 6. Sara is 6 years old now, meaning that Ralph is 3(6 years), or 18 years old.
Ralph's current age is 18.
B. -2 is the aswers
hope it help... :)
<span><span> x2-15=0</span> </span>Two solutions were found : <span> x = ± √<span>15 </span>= ± 3.8730</span>
Step by step solution :<span>Step 1 :</span>Trying to factor as a Difference of Squares :
<span> 1.1 </span> Factoring: <span> x2-15</span>
Theory : A difference of two perfect squares, <span> A2 - B2 </span>can be factored into <span> (A+B) • (A-B)
</span>Proof :<span> (A+B) • (A-B) =
A2 - AB + BA - B2 =
A2 <span>- AB + AB </span>- B2 =
<span> A2 - B2</span>
</span>Note : <span> <span>AB = BA </span></span>is the commutative property of multiplication.
Note : <span> <span>- AB + AB </span></span>equals zero and is therefore eliminated from the expression.
Check : 15 is not a square !!
Ruling :<span> Binomial can not be factored as the difference of two perfect squares.
</span>
<span>Equation at the end of step 1 :</span><span> x2 - 15 = 0
</span><span>Step 2 :</span>Solving a Single Variable Equation :
<span> 2.1 </span> Solve : <span> x2-15 = 0</span><span>
</span>Add 15 to both sides of the equation :<span>
</span> <span> x2 = 15</span>
<span>
</span>When two things are equal, their square roots are equal. Taking the square root of the two sides of the equation we get: <span>
</span> x = <span> ± √<span> 15 </span></span><span>
</span>The equation has <span>two real solutions <span>
</span></span>These solutions are <span> x = ± √<span>15 </span>= ± 3.8730 </span><span>
</span>
Two solutions were found : <span> x = ± √<span>15 </span>= ± 3.8730</span>
Answer:
a octagon, convex.
Step-by-step explanation:
an octagon has eight sides
convex because its figure is projecting outwards