Question
Solve the quadratic equation
Solve using the quadratic formula
Solve by completing the square
Solve using the PQ formula
x1=52−39,x2=52+39
Alternative Form
x1≈−0.849,x2≈1.649
Evaluate
5x2=4x+7
Move the expression to the left side
5x2−4x−7=0
Substitute a=5,b=−4 and c=−7 into the quadratic formula x=2a−b±b2−4ac
x=2×54±(−4)2−4×5(−7)
Simplify the expression
x=104±(−4)2−4×5(−7)
Simplify the expression
More Steps

Evaluate
(−4)2−4×5(−7)
Multiply
More Steps

Multiply the terms
4×5(−7)
Rewrite the expression
−4×5×7
Multiply the terms
−140
(−4)2−(−140)
Rewrite the expression
42−(−140)
If a negative sign or a subtraction symbol appears outside parentheses, remove the parentheses and change the sign of every term within the parentheses
42+140
Evaluate the power
16+140
Add the numbers
156
x=104±156
Simplify the radical expression
More Steps

Evaluate
156
Write the expression as a product where the root of one of the factors can be evaluated
4×39
Write the number in exponential form with the base of 2
22×39
The root of a product is equal to the product of the roots of each factor
22×39
Reduce the index of the radical and exponent with 2
239
x=104±239
Separate the equation into 2 possible cases
x=104+239x=104−239
Simplify the expression
More Steps

Evaluate
x=104+239
Divide the terms
More Steps

Evaluate
104+239
Rewrite the expression
102(2+39)
Cancel out the common factor 2
52+39
x=52+39
x=52+39x=104−239
Simplify the expression
More Steps

Evaluate
x=104−239
Divide the terms
More Steps

Evaluate
104−239
Rewrite the expression
102(2−39)
Cancel out the common factor 2
52−39
x=52−39
x=52+39x=52−39
Solution
x1=52−39,x2=52+39
Alternative Form
x1≈−0.849,x2≈1.649
Show Solution
