Answer:
B. 80°
Step-by-step explanation:
55+45=100
180-100=80
Q=80°
Answer:
x = -1
y = 5
Step-by-step explanation:
x+y=4
3x+7y=32
<em><u>To solve a pair of equations using substitution, first solve one of the equations for one of the variables. Then substitute the result for that variable in the other equation.</u></em>
x+y=4,3x+7y=32
<em><u>Choose one of the equations and solve it for x by isolating x on the left hand side of the equal sign.</u></em>
x+y=4
<em><u>Subtract y from both sides of the equation</u></em>.
x=−y+4
<em><u>Substitute −y+4 for x in the other equation, 3x+7y=32.</u></em>
3(−y+4)+7y=32
<em><u>Multiply 3 times −y+4.</u></em>
−3y+12+7y=32
<em><u>Add −3y to 7y.</u></em>
4y+12=32
<em><u>Subtract 12 from both sides of the equation</u></em>.
4y=20
<em><u>Divide both sides by 4</u></em>.
y=5
<em><u>Substitute 5 for y in x=−y+4. Because the resulting equation contains only one variable, you can solve for x directly.</u></em>
x=−5+4
<em><u>Add 4 to −5.</u></em>
x=−1
To determine the time it will take for the diver to reach the water below, we derive the equation such that t will be our unknown and that will be,
t = √(d/4.9)
Substituting the known values,
t = √(70 m / 4.9) = 3.78 s
Therefore, it will take the diver approximately 3.78 seconds to reach the water below.
Answer:
41 minutes
Step-by-step explanation:
Step one:
given data
Susan purchased a prepaid phone card for $15
let the number of minutes be x
and let the total be y
per minute call cost = 14 cents = $0.14 per minute
Hence the expression for the situation is given as
y= 15-0.14x
Step two:
given that the balance after a call is 9.26
9.26=15-0.14x
solve for x
9.26-15= -0.14x
5.74=0.14x
divide both sides by 0.14
x=5.74/0.14
x=41 minutes
To solve this problem you must apply the following proccedure:
1. You have that <span>25-foot long board is to be cut into two parts. Then, the first equation is:
a+b=25
2. </span><span>The longer part is one foot more than twice the shorter part:
a=1+2b
3. The system of equation is:
a+b=25
a=1+2b
4. When you solve it, you obtain:
a=25-b
25-b=1+2b
25-1=2b+b
24/3=b
b=8 ft
a=1+2(8)
a=17 ft
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