SOLUTION: Please help me solve these problem. t^2-2t=15 0.9a^2+5.4a-4=0 x^2+10x+c Find C Thank You So Much!

Question 197874: Please help me solve these problem.
t^2-2t=15
0.9a^2+5.4a-4=0
x^2+10x+c
Find C
Thank You So Much!
Answer by jim_thompson5910(35256) (Show Source): You can put this solution on YOUR website!
# 1

Start with the given equation.

Get all terms to the left side.

Notice we have a quadratic in the form of where , , and

Let's use the quadratic formula to solve for "t":

Start with the quadratic formula

Plug in , , and

Negate to get .

Square to get .

Multiply to get

Rewrite as

Add to to get

Multiply and to get .

Take the square root of to get .

or Break up the expression.

or Combine like terms.

or Simplify.

So the solutions are or

# 2

Start with the given equation.

Multiply EVERY term by 10 to make every number a whole number.

Notice we have a quadratic in the form of where , , and

Let's use the quadratic formula to solve for "a":

Start with the quadratic formula

Plug in , , and

Square to get .

Multiply to get

Rewrite as

Add to to get

Multiply and to get .

Take the square root of to get .

or Break up the expression.

or Combine like terms.

or Simplify.

So the solutions are or

# 3

Are you looking for the value of "c" that will make a perfect square??? There are no other instructions?

If so, then take half of 10 to get 5. Square 5 to get 25. This means that

So the expression is which is a perfect square.

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