It looks like your equations are
7M - 2t = -30
5t - 12M = 115
<u>Solving by substitution</u>
Solve either equation for one variable. For example,
7M - 2t = -30 ⇒ t = (7M + 30)/2
Substitute this into the other equation and solve for M.
5 × (7M + 30)/2 - 12M = 115
5 (7M + 30) - 24M = 230
35M + 150 - 24M = 230
11M = 80
M = 80/11
Now solve for t.
t = (7 × (80/11) + 30)/2
t = (560/11 + 30)/2
t = (890/11)/2
t = 445/11
<u>Solving by elimination</u>
Multiply both equations by an appropriate factor to make the coefficients of one of the variables sum to zero. For example,
7M - 2t = -30 ⇒ -10t + 35M = -150 … (multiply by 5)
5t - 12M = 115 ⇒ 10t - 24M = 230 … (multiply by 2)
Now combining the equations eliminates the t terms, and
(-10t + 35M) + (10t - 24M) = -150 + 230
11M = 80
M = 80/11
It follows that
7 × (80/11) - 2t = -30
560/11 - 2t = -30
2t = 890/11
t = 445/11
Answer:
40.5 is what they are divided
Step-by-step explanation:
25% because 19+57= a total of 76 students and the percentage of 19 out of 76 is 25%.
19/76= 0.25
Answer:
30.6452% decrease.
Step-by-step explanation:
%
100-69.354 ≈ 30.6452%
Answer:
The given expression is simplified as 
Step-by-step explanation:
Here,the given expression is (x+9)(x -9)
Using the ALGEBRAIC IDENTITY:
Now, here in the given expression (x + 9)(x -9)
Comparing it the left side of the identity,
we get a = x
and b = 9
The right side of the equation is 
Substituting the value of a and b, we get
⇒ 
= 
Hence, the given expression is simplified as
