not sure. but the answer is 8 .
Linear combination method just means to add the equations so that one variable with cancel. In this case the a values are already set up so that they will cancel.
2a + 3b = 1
-2a + b = 11
4b = 12
b = 3
now put 3 back into either of the original equations and solve for a.
2a + 3(3) = 1
2a + 9 = 1
2a = -8
a = -4
(-4,3)
$10120×1.15=$11638
$11638×1.10= $12801.80
$12801.80 were raised 2 years ago.
Basically, this problem wants you to solve the area of the trapezoid given those dimensions, then multiply this to the unit cost to determine the total cost. The formula for the area of trapezoid is written below:
A = (a+b)h/2, where a and b are the lengths of the two bases
A = (15+9)(10)/2 = 120 cm²
Total Cost = 120 cm² * $0.80/cm² = <em>$96</em>
Answer: the one that ends with 30. D the fourth one
Step-by-step explanation: