Let x = number of problems on test
If he got 14 wrong, then x - 14 is the number correct.

x - 14 = .72x
.28x - 14 = 0
.28x = 14
x = 50
The test consisted of 50 problems.
Answer:
-2xl -2y + 99
Step-by-step explanation:
Given data:
The given distance is d=26 km.
We know 1 kilometer is equal to approx 0.621 miles.
1km= 0.621 miles
Multiply the above expression with 26 on both sides.
26(1 km)= 26(0.621 miles)
26 km= 16.146 miles.
Thus, 26 kilometer is equal to 16.146 miles
Answer:
see explanation
Step-by-step explanation:
Given
4
- 5a² + 1 = 0
Use the substitution u = a², then equation is
4u² - 5u + 1 = 0
Consider the product of the coefficient of the u² term and the constant term
product = 4 × 1 = 4 and sum = - 5
The factors are - 4 and - 1
Use these factors to split the u- term
4u² - 4u - u + 1 = 0 ( factor the first/second and third/fourth terms )
4u(u - 1) - 1(u - 1) = 0 ← factor out (u - 1) from each term
(u - 1)(4u - 1) = 0
Equate each factor to zero and solve for u
u - 1 = 0 ⇒ u = 1
4u - 1 = 0 ⇒ 4u = 1 ⇒ u = 
Convert u back into terms of a, that is
a² = 1 ⇒ a = ± 1
a² =
⇒ a = ± 
Solutions are a = ± 1 , a = ± 