Answer:
49
Step-by-step explanation:
devaughn= x+15
sydney= x
set an equation adding both their ages
x+x+15=113
2x+15=113
subtract 15 from both sides
2x=98
x=49
sydney is 49
Answer:
y=kx
subst y=10 and x=20 into the above
<em>1</em><em>0</em><em>=</em><em>k20</em>
<em>k</em><em>=</em><em>1</em><em>0</em><em>/</em><em>2</em><em>0</em>
<em>k</em><em>=</em><em>1</em><em>/</em><em>2</em>
<em>therefore</em><em> </em><em>relationship</em><em>:</em><em> </em><em>y</em><em>=</em><em>1</em><em>/</em><em>2</em><em>x</em>
<em>subst</em><em> </em><em>x</em><em>=</em><em>1</em><em>5</em><em> </em><em>into</em><em> </em><em>the</em><em> </em><em>relationship</em>
<em> </em><em>y</em><em>=</em><em>1</em><em>/</em><em>2</em><em>(</em><em>1</em><em>5</em><em>)</em>
<em>y</em><em>=</em><em>7</em><em>,</em><em>5</em>
Step by step explanation:
- Step 1: when they say y varies directly with x they mean<em> y is proportional to x</em>
- step 2: so y=kx where <em>k is the constant</em>
- step 3: is to substitute <em>y=10</em> and <em>x=20</em> into the above equation y=kx
- step 4: you will end up with <em>10=k20</em> then divide both sides by 20 so that <em>k becomes the subject of the formula </em>
- step 5: your answer from the above will be <em>k=10/20 </em>so the relationship is <em>y is directly proportional to 1/2 x </em>what you did here is that you substituted k for 1/2 in the equation in step 3
- step 6: is to finally substitute x=15 into the equation <em>y=1/2x</em> to finally get your answer <em>y</em><em>=</em><em>7</em><em>,</em><em>5</em><em>.</em>
Where x is the length of the first piece

so the first piece is 3 inches, the second is 6 inches and the third is 19 inches
1. 2x^2-x-15=0
A = 2
B = -1
C = -15
2. 10^2-2x=0
A = 10
B = -2
C = 0
3. x^2–3x-40=0
A = 1
B = -3
C = -40
4. x^2+3x-2=0
A = 1
B = 3
C = -2
5. 4x^2-17x+8=0
A = 4
B = -17
C = 8
Remember the equations should look like Ax^2+Bx+C=0 (in this order!!)
Answer:
45
Step-by-step explanation:
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