Question 375921
Let x be the amount of increase.
{{{(4+x)(5+x)=56}}}
{{{20+4x+5x+x^2=56}}}
{{{x^2+9x+20=56}}}
{{{x^2+9x-36=0}}}
{{{(x+12)(x-3)=0}}}
Two solution but we only want the positive one.
{{{x-3=0}}}
{{{x=3}}}
{{{4+3=7}}}
{{{5+3=8}}}
The new garden is 7m by 8m.