7/x = 5/y
Can be changed to:
5x = 7y
So, x = (7/5)y and
y = (5/7)x
10x + 40 = 100
A restaurant owner sells each plate of rice for 10 dollars plus an additional 40 dollars for the entrance. Mack goes to that restaurant and pays 100 dollars in total. How much plates of rice did he order?<span />
Alrighty
remember
means
and
and
for all real values of x
so
means
means
which simplifies to
1=x²+4x-5
minus 1 both sides
0=x²+4x-6
use quadratic formula or complete the square
and
2 solutions
Answer:
x = 9/2.
Step-by-step explanation:
2/3 x + 4 = 7
2/3 x = 3
Multiply both sides by 3/2:
2/3 * 3/2 x = 3 * 3/2
x = 9/2.
I know of two ways to solve quadratic equations. The first is through factoring. Let us take the example (x^2)+2x+1=0. We can factor this equation out and the factors would be (x+1)(x+1)=0. To solve for the roots, we equate each factor to 0, that is
x+1=0; x+1=0
In this case, the factors are the same so the root of the equation is
x=1.
The other way is to use the quadratic formula. The quadratic formula is given as [-b(+-)sqrt(b^2-4ac)]/2a where, using our sample equation above, a=1, b=2 and c=1. Substitute these to the formula, and you will get the same answer as the method above.
